Need to fix existing ones first,
1) WSG Graveyard needs a protective bubble, teams should not be able to attack each other in this (Obviously Flag can't be taken in)
2) AV Bosses need to be scaled/buffed based on gear, plus an increase in Resource Limit to 1000
3) Graveyard Protection also for AB and EotS entry points, plus Graveyards in TP and DWG.
4) Redesign SSM as it is one of the crappest design maps in terms of balance I've ever seen.
5) Add flags to EotS Bases, similar to the Rated Version
6) Better scale the Defense Turrets in SotA, so they're viable
On top of this, I would also like to see,
1) Tol'Barad, Ashran and Wintergrasp added to the PVP Que
2) New AV Version with 3000 Resources and much stronger bosses for a longer game
3) New IoC Version with increased Keep durability and slight revamp for longer games
4) New IoC, New AV, Tol'Barad, Wintergrasp and Ashran classed as Large Scale Warfare as an option for separate que
5) WSG, AB, EotS, SotA, TP, SSM, DWG and ToK classed as Small Scale Warefare as an option for separate que
6) All current Battlegrounds listed as a Classic option que (WSG, AB, AV, EotS, SotA, IoC, TP, SSM, ToK and DWG
7) All Large Scale, Small Scale and AV/IoC classed as Call to Arms/Random que
Pretty much a revamp of current que options, to give players a choice in what to play into Classic/Current, Large Scale, Small Scale and Random. Let's players choose their favourite style of PVP based on Team size and game duration, with an option to still blacklist a Map of that current pick.
On top of this, I'd also want to see visual updates to WSG, AB, AV and EotS.