Busters:
- dmg calculation lowered down to the original atk*rap and atk*chrg*4
- NCP price increases back to the original
- Normal buster attack dmg added to all of your hits (including multihit, AoE attacks, and charged attack)
- Charged attack takes up only one action (so one action= atk*chrg*4)
- New NCP parts (effects to charge attacks, regen, shield), adjustments to existing ones.
Chips:
- New value (mb), calculated from dmg and other effects, similar to signature attacks.
- Aside/instead of the existing 30 chip in folder limit, a capacity limit is added (basically, the equipped chips mb total has to be lower). This means that better chips take up more space.
- New navi-item that extends capacity limit.
Levels:
- Chips not counted in levels. Instead, signature attacks, mb capacity expanders, and perhaps chip library is.
Alright, let's see why I think these changes are cool/useful.
Busters:
Busters, as of now, don't serve a purpose. Swords can replace them entirely, while being cheaper, and even having extra effects, such as elements or AoE. Even if you buff them more, they are too expensive. If you make them cheap and powerful enough to compensate for the effects, THEN busters replace chips, so that is not the way to go either. So, my idea was to make them more of a... stat. Busters become something like what STR is in other games; thus you can ignore them and get equipment instead, or split your resources between the two, or go full stats. But what makes any combination viable?
Mb:
This limits the power / number of the chips that a navi can use. It also gives a basic idea of the power of thew chip, that is possible to use to count levels (should you not like my alternate lvl suggestion), use as basis for trades (preventing abuse). The main reason for is, however, is to force players to choose chips that they want to use. Right now, its pretty much just using your strongest chips, and possibly (only possibly) changing your folder when you go into an element heavy place. But why would you do that when out of 30 chips you can have some against all elements? Although, it seems a lot of hassle to caluclate the MB of chips, if there is an easy to remember formula, it can be calculated on the spot ((dmg+effects)*type/strongereffect*constant)). Then again, one more value shouldn't be too difficult to remember.
This is just a rough draft of the calculations and can be changed: You'd start out with a bit more space than your starting chips. Upgrades would be going like 1000 + 1000 after every upgrade (so 1000, 2000, etc...). One upgrade would add the same amount as your starting folder.
Levels:
Chips numbers being counted in lvls is a pretty obscure idea, since it is a dinamically changing number. Some change is needed, even if you don't like my suggestion. It opens up several ways for abuse, if nothing else than trading chips, or fast grinding in ACDC just for levels. Zan already did a post in the modcave with an idea of tiering the chips, but that won't work me thinks. Mb value would be good, but it doesn't fix the fact that you can aquire levels that you can sell

Chip library would work pretty much like the current level based on chip system, but every chip you ever had would only count ONCE (and you can't loose the chip data from the library, obviously). This promotes member interaction and trades, but this is my least liked lvl idea out of this bunch, but it was in the games so why not?
Signature attacks counting should've happened a looooong time ago.
Mb capacity expanders, thats my suggestion so I inherently like it.
If you don't like any, then my final suggestion is to base one off of mb value. Tiering isn't bad, but it isn't precise enough. Its basically the number after the chip name

As explained in the mb suggestion it should not take too much to remember/calculate one more value.