Allies seemingly allows players to patch a few holes in their armies. However, is there something you wish your army did better or is there a unit that you think is missing from your codex that you wish you could field? For example; do you wish IG had better psykers? Do you think Dark Eldar need some sort of giant robot to match their older brothers?
For me, I wish Orks had better armor mitigation. I liked the last codex's choppa rules more than I do now because I still can't seem to pop power or termie armor very, despite getting 30 orks throwing lots of dice. Getting past AV14 is also a big problem, outside of hand-to-hand too.