Weapons:

All weapons are fine, except the LG. They should either tweak again the hitreg or keep it as it is but make it do 8dmg/hit instead of 7dmg/hit (currently).
Not saying that cause I'm an LG abuser, just that I want the holy trinity (RL LG RG) to be as much balanced as possible.
At the moment most pros players just ignore the LG, it's ridiculous to see how this game has become RL-only. The railgun is fine tho. You also have to take into consideration that most light champions are very fast, so rushing with RL becomes easier.
For all of those reasons, LG needs a buff, so that people like evil, strenx, clawz can play their favorite playstyle again (LG-based playstyles). That said, even with a LG buff, the game would still be balanced and open to a lot of different playstyles (RG-heavy, RL-heavy or LG-heavy).

Champions:

Currently there are 3 different tiers of champions. Top-tier are slash, anarki, doom and nyx. Middle-tier are sorlag, ranger and clutch. Sub-tier are galena, scalebearer, B.J. and visor.
You can either nerf the top-tier champs, or buff the sub-tier champs.
At the moment, it's ridiculous to see that 90% of the best players are using slash, anarki and doom/nyx.
We don't want a game with "Overwatch-like-approach", where some champions/heroes are definitely better than the rest. We want a perfectly balanced game, where every players can just pick his favorite champs based on their own playstyles.

Quake has always been about balance and letting the players develop their own playstyle/way of winning.
It's sad to see that at the moment QC is only about rockets and light & fast champions with a lot of mobility.