What would be the point to become sniper after hunter? Can we get skills from hunter and sniper combined and then add ranger skills? Or what would be benefit? For me it just seems to be a bit of time wasting if there is no benefit from becoming a sniper...
When you rebirth/trans your stats are reset to 1 so it's a good chance to fix up your build if it's gone wrong
What job should I choose for my new character that would be good for MvP grinding?
MVP grinding is pretty hard unless you have some good gear and/or you know the MVP's elemental weakness, racial reductions etc. Good MVP jobs are probably Gx, Geneticist, Sura (the main three), but it's quite possible to MVP with other jobs if you have the correct resist gear, pots etc. In my opinion, however, you would be better off finding a support role (especially arch bishop) in which you would easily be able to find parties in turn-ins (turn-in = exp + EMB = money $$) and assist people when they're MVPing or doing instances (don't do it for free obviously - make them share the loot).
In the case that you have no clue what turn-ins are, check this out http://irowiki.org/w..._Turn-In_Events