We, players, are the ultimate hivemind for suggestions. We've had so many suggestions to improve things but who'd listen to us.
As for me, I'd add add a 3 second countdown before the 1v1 match starts and lock them in combat for the entire duration of the match. I think it's unfair how some classes clearly have much better openers, while others, like KFM, struggle. I've seen so many kfms having to waste their ice just to stop me from windwalking. Wallbanging should not be a thing either but if you look at trial arena Force Masters, they throw you against the wall and wallbang you to death. That's how the devs progammed them; I guess removing wallbang would require a class rework. The newest class, dual blade, does a similar thing. They just knock you back forever so you can't tab or wallbang you like FM. This makes me think they've completely given up on trying to make classes work in pvp. Maybe they've given up since warden. I feel like we have too many specs now and it's getting harder and harder to balance them. However, what they can do is to not make them broken. 3rd spec sin is not strong. It's not OP. It's broken. I have mixed opinions about 3rd specs. I don't feel like we needed them. The game did just fine with 2 specs. But I understand that some people really enjoy them and I have seen people rerolling to another class because it had a cool 3rd spec. I don't like 3rd specs because I hate mine and I get upset when I see other classes being absolutely broken because of it.
I gave up on 6v6. There is just too much stuff, too much gear that F2P players don't bother with. I just get depressed when I see dudes having 2x more AP, 2X more defense, 1.5x more hp, 3x more crit defense, etc...If I were to make some changes, I'd start by adding all the pvp accs to the bg trader. I don't mind paying 25k battle points and 200 moonstones for it. He already sells gloves and bracelet, so why not add the rest? I'd also introduce balanced 6v6 and experiement with it (maybe the stats from 1v1 would not exactly work there) but I feel like we just don't have enough players interested in pvp to play it and give feedback. They can encourage players to play pvp by adding 2 vials/week to the trader. Like, winning/participating/weekly pvp quests give you a currency that you can exchange for vials. I don't know if this would actually work but I'm just one person out of many who can come up with suggestions. Other than that I don't care, I only play pvp for season rewards, not for fun.
I'm ranting but I don't really know what else to do. People have already suggested all kinds of solutions for the problems we have but no one cares about us.