The first sweeping change is what DNA would be. Instead of being related purely towards skills, they would also encompass character traits
The second sweeping change is how characters gain DNA. The player gains them through quests, from drops, as rewards from PVP, and automatically as they level up.
The third sweeping change is the player can freely altar their DNA in usage through an NPC. This would require the player to return to town, but they can re-arrange their DNA through a window similar to the one below.

*Image Legend:
Red Bar - Currently unusable slots.
Different Glows - Different types of DNA effects.
Faded out DNA Sequence - Unobtained.
unfaded DNA Sequence - Obtained.
Highlighted DNA Sequence - In use.
The final sweeping change is the player would gain stat bonuses, skills, or traits if they put the DNA in a certain order. Figuring out the order can be done through trial and error, or by finding information on certain DNA sequences. Maybe they would find an information disk on a mob that has a sequence, but its data is corrupted and its missing a couple in the sequence that the player must figure out.