Content -
In general I would really like to see more jumpships, even LF variants that have been talked about before. I know regular jumpships aren't the flashiest but it's just insane how many more warship designs we have than jumpships and yet warships are supposedly rarer. In general I like seeing content that fills holes in unit types and gives us stats for things that have been mentioned but never gotten any stats and/or TRO writeup.
Writing -
I particularly enjoy the short stories about how the unit has been used in-universe, the pilot writeups, and the quirks that said unit might have.
Rules -
I'm not crazy about extra rules in TRO's, maybe new equipment like 2750/3050 while we wait a few months or so on an updated rulebook.
Art -
Fairly happy with the current Battletech art direction although it does bother me when there will be just a few sketches in each TRO that get lax on detail, like the 3075 Eyleuka & Hyena, 3085 Trajan or Prototypes Enyo, not that I dislike the art in questions, it just seems unfinished. Not a fan of the over the top totem mechs or things like the Gen1 Protomechs but appreciate the variety as long as such designs remain rare and unusual.
Layout -
I really prefer the same unit types be together, battlemechs, vees, fighets, etc with only possible exception being divisions by technology base. It's definitely knowing which units are used by which factions but found the 3075 style faction sections to be a bit much. IMO the perfect TRO has an overall layout like Prototypes but with a somewhat more traditional page layout as seen in 3085.