I think the two super big things that I (and probably most people) want to see are the Skill Rebalances and the Fever Fields (with their unique equipment).
Weapon option changes are good so far. I think the increase in drop rate of all weapons is really good. 0.25 is a pretty good spot for most weapons I think, though I would probably raise the quality of the options available if it was going to stay there. A raise to 1~5% drop rate like on kRO Zero wouldn't be bad either, with the way options look now - obviously this would require dropping the sell price of all optioned weapons. Really looking forward to seeing what the advanced tiers of options look like tomorrow.
One thing I'm really excited for is seeing the Option system expanded into non-weapon gear. Probably not accessories or headgears, but basically every other slot would benefit greatly from them - though the list of mobs that drop optioned armors would need to be expanded, with a similar boost to drop rates to what weapons got. 0.1 for higher tier gear to 0.5 for lower tier gear is a pretty good spot imo, though again that's significantly lower than we see working on other servers, so I might improve the quality of options if we keep it that low. Alternatively, the champion mob system (either the current renewal one, or the one where one spawns for every X kills of the normal mob) would be a great way to distribute those gears.
Dangerous dungeons...we don't really know anything about them yet. Looking forward to seeing what these are all about, and what kind of gear is going to drop from them - also sounds like a good way of distributing optioned armor and weapons at higher rates than normal maps. If these are something you can develop and implement without involvement/with minimal involvement from Korea, that's probably where I would focus most of my efforts. This seems like the easiest and most fun way to differentiate RT from other servers, so I think it should take a good chunk of the priority for updates.
As far as changes we've already seen, I think basically everything has been positive so far. New systems seem objectively good (though some kinks still need to be worked out, here's looking at you RODEX search feature). Pet system is overall kinda minor, but good. Homunculus change is great, though the death of the AI is unfortunate. Monster stats and EXP have been changed so often it's kind of hard to get a grasp on where exactly they all stand, though I can't think of anything too particularly offensive that I've come across.
I'm sure the staff is sick of hearing this by now, but of the Zero stuff I want to see besides above, I'd love to see the Zero champion system (every X number of mobs killed spawns a champion version of that mob on the person that killed the last one) and the mini-MVPs that go with it. I believe there was an MVP version of Arclouze, High Orc, Penomena, Bathory...maybe a few more? Also the changing of Bloody Knight into an MVP for Chiv 2 was a cool idea. Along with that, the changing of card effects seems like an objectively good idea - fixing the much weaker MVP cards like Doppel and Osiris, and toning down the super strong MVP cards like GTB.
One big thing I'm curious to hear is the plans for Class progression on this server. Will we go the standard 99 > Trans 99 > 3rd job? Or will we follow the Zero route of 99 > Trans 120~130 > ???. Judging from what we've seen so far, it looks like the former is probably the plan, but we were told this is an "improvement on the Zero system." If we see the skill changes, I think the latter system is probably more appropriate, though I'm sure there are many people who would vehemently prefer one or the other. Which way we go will have a pretty big impact on how future content is added to the game, so I think knowing this sooner rather than later would be beneficial to everyone involved.
Instances...I don't know how difficult it is for you guys to develop custom instances. It may be better to just grab the ones from Korea made for Zero, if at all possible - though they may be a tad difficult for us until we've got the new gear and skill changes to bring us closer to their power level. If it's possible to make these custom, I think they'd make a great complement to the Dangerous Dungeons as ways to set apart RT from other servers, and distribute new kinds of gear not available elsewhere in the game. The kind of low-intensity, short duration instances that Zero got near the start are a good place to begin I think, either copied from them if necessary or used as inspiration if we are capable of building our own.
Quests...I'm not a terribly big fan of quests in RO. Content like dungeons being locked behind them is a huge pain if you have more than one character you want to take there, and daily type quests rapidly become chores rather than fun content. That being said, new content is new content, so as long as the rewards make it worth my time to do them, I'd be happy for things like storyline quests, or more difficult quests linked to the Dangerous Dungeons - these could reward gear obtainable from the dungeon, or even stuff that would otherwise be cash shop exclusive, like battle manuals, gum, and other consumables. I know Zero has dailies that give cash shop consumables and potion boxes but...considering the experience with Restart, I'm a bit hesitant to recommend the latter of those.
Cashless ways in game to achieve Enriched/HD Ores and Blacksmith Blessings is a big yes if the new gears we will get are going to be as reliant on upgrade levels as they are now in Renewal, or on kRO Zero. I don't have any particular issue with ores in the Cash Shop, but a way to get them in game, perhaps from Dangerous Dungeons/Fever Maps or quests related to them, or crafting them out of the normal ores, goes a long way to mitigating the p2w aspect of those refine-hungry gears.
That being said, I'd also like to see the refine bonus changes to armor refines - where armor refines give a lot more defense than they currently do on Renewal (10 defense per refine on 1~4, then 20 on 5~8, then 30 on 9~10). I'm not sure how effective even that change makes armor refining, but it at least doesn't look completely useless like armor refining is in Renewal right now.
Overall, I was hoping the changes to RT would be a lot more drastic than they seem after the first week of tests. But the changes we do have are certainly covering a good chunk of ground, and almost all of them have been very positive. If I had to list what I want to see in order of importance, it would be something like:
1. Skill Balance Changes
2. Fever Maps/Dangerous Dungeons and their respective gears
3. System Changes (Monster/Drop rate tuning, refining changes, questing changes, expanded Weapon/Armor Options, etc etc)
Things I want more information on in order of importance,
1. Dangerous Dungeons
2. Class Progression (standard Renewal Progression? Zero progression? Something new?)
3. Cash Shop contents
All in all, I'd say I'm pretty optimistic about RT. Again, many of the drastic changes I wanted to see seem like they'll be a bit aways still, but at the rate things have been added/changed in the CBT, I feel like we'll probably be in a pretty good spot by the time we get to OBT/Official launch.