The reason why low level PvP is so imbalanced is because Blizzard had no clue as to what they were doing when they released classic WoW.
Case in point: T3 raiders were in the BG's destroying the players who were wearing the BG sets. There was so much more hit and crit on raid gear, not to mention set bonuses and the better stats. Blizz's answer to that was resilience in BC. Instead of just buffing the BG gear at the time, they release the most complained about, unbalanced/unbalancing stat in the game to date. How many times have developers said "Get to end game and resilience will fix it." and nothing is still fixed or better??
The best way to "balance" PvP gear wise is to make raid gear and PvP gear the exact same. BUT, lower the item level of PvP gear to the point to where you can't get into a raid with it. OR, raise the item level requirement on raids so that people in full PvP gear can't get in. That way people will have access to equal gear and the games will boil down to comp selection and skill.
The next way to fix PvP is to make everything scale with level. They've done away with ranks for spells, so why buff flat across the board and make low level PvP unbalanced?? With a 15% buff to explosive shot, it would take an idiot to not see how it would unbalance things at low level. This leads a lot of people to believe that Blizzard simply just doesn't care and lacks the foresight of their actions.
Another example of Blizzard's massive stupidity, is allowing BC enchants to be used on classic wow gear. Mongoose at 39? While it's fun to get it and wreck people, it again leaves players wondering if Blizzard knew what kind of impact expansions would have at lower levels. It's almost like Blizzard said "F*ck it, we'll leave low level PvP so incredibly unbalanced and intolerable that people will get frustrated and move to end game." Without realizing that until you have everything balanced in the beginning, the end won't be balanced either. If you have a sh*tty foundation, your home will be encountering lots of problems in the future.