Every gun has its purpose, you don't need to spend much time in the game to learn which weapon is appropriate to use in which situation. The main weapons to use are the Rocket Launcher at close-mid range, the Ioncannon at close range and the Boltrifle at long range. Plasma is used for movement, area denial and sometimes as a weaker Ioncannon alternative, Shotgun is mainly used in TDM and FFA as a weaker alternative to Ioncannon or as a close range finisher, Grenades for traps and area denial. Burstgun is the starting weapon, its only purpose is to not leave you completely defenseless on spawn. Removing any weapon from the game would take away a vital part of the gameplay.
The game is similar to QL, however it's a spiritual successor to the Quake 3 mod CPMA, there are a few differences, most noticeably in movement and the armor system. The maps you recognize from QL have been licensed, iD Software doesn't own them.
Getting wrecked in 1v1 as a new player is fairly normal, i never played the game you used to play, but it seems fairly different, so i wouldn't be surprised if not an awful lot of skills you gathered in that game carry over well. Reflex also amplifies the skill difference between players quite a bit, score differences in the double digits between fairly evenly matched players aren't uncommon.
Currently the game balance is being worked on by members of the community, so you can be sure that the community is being heard.