It's a big thread, and a lot of my thoughts have been already stated but some of the most importance..
1) Meta!!A lot of games (video games etc) use this pretty tool that makes the game change once in a while with buffs/nerfs,changes that makes it feel alive and much more interesting.Making the Warscrolls a living update pool with frequent changes gives you the chance to use all of your favorite models since the meta will change and not just sticking to "Kunnin Rukk" lists.
2)Base measuring
3)Initiative. Some ppl hate it some love it when theyre lucky. I dont know how i really feel about this one but i think it would be more "fair" if the initiative had the chance to change in each different phase. Roll at hero phase, do your things, roll in movement, move them as you like etc. It would unlock some better and with more depth decision making.
4)Movement. I would love to see some bonuses/penalties when crossing difficult terrain,forests,rivers