Basically this is a call for the DDO devs to do a little bit of work, not with AI so much, but with hireling stats and ways to improve them to make them a little better.
I have two basic paths of suggestions of these sorts listed as follows...
1. Give hirelings feats, gear, and enhancements that players are likely to take. The important ones are quicken and PrE's. There are a few wizard hirelings which really should be PMs for example and pretty much every mid to high level healer needs quicken because they will sit in the middle of cleaving mobs or traps trying to heal themselves. Also, toughness and some enhancements for HP never hurt anyone. Better geared hirelings might cost a little more to hire, but would be greatly appreciated. This is basically a devs tweaking the hirelings to be better and closer to players type of suggestion.
2. Let players assign gear to hirelings. Basically there would be a tab for each hireling that looked like your cloth doll with their gear in there normally. You could then drop in gear of your choice to replace their gear (or remove that gear to have their default gear take over). The gear would never leave your inventory tabs and would just be used by the hireling. For ease of use full gear sets could be setup like we can do with weapons and applied with a single button. Hirelings could not use any equipment you currently have equipped. This would provide players with a way to twink their hirelings if they wanted to, but would require them to carry around extra gear for these purposes. NOTE, this could be extended to 'lending' gear to other party members who are real players also in a similar manner except with some sort of check box on the gear setting it to 'loan' mode that other players can access while in party (of course only one at a time can equip though).