I have played a few other tactical RPGs over the years, and here are my thoughts on the ones that come to mind.
FF Tactics; (GBA and DS)
I haven’t touched the FF Tactics series in a long time. I spent the most of my time playing probably A2, then followed by Advanced and last by XII:Revenant Wings. I was pretty young then so I didn’t really think much about strategy depth in that sense so I got screwed over a lot by judge rulings and the more advance classes.
Symphony of War: The Nephalim Saga. (PC - Steam)
This one is probably the most recent non FE Tactical RPG I’ve played. It uses a customisable squad system, which is pretty neat. I’ve drawn two characters from it too (Beatrix and Diana). Some people liken it to Tactics Ogre, but I haven’t played that series so I can’t vouch for that sentiment. Its a neat shortish game so if this sounds interesting I can suggest it. They’re also working on a sequel.
XCOM Remake and XCOM 2
This series is probably the one I’ve played the most outside of Fire Emblem and the remake has a number of RPG mechanics that make it feel like a proper Tactical RPG rather than just a tactical game. Especially with the 2nd game’s major DLC the War of the Chosen. On my steam library it is currently only outplayed by 4X games (+Total War 3 Kingdoms) and Baldurs Gate 3. So thats my endorsement for this series. It has all the the Fire Emblem staples you love. Percent chance hit rates with bullshit enemy crits and enemy dodge rates. A support bonding system (although you’re gonna have to head cannon support convos and backgrounds). A neat skill system if you have the WotC DLC and/or mods.
Super Robot Wars/Taisen Series (DS/3DS/Switch/Steam - PC)
I’ve played a few of these and it helps a lot that I enjoyed a lot of the anime series involved. In fact this series introduced a few of those animes that have become my all time favourites. This series has goated animations. If you though the GBA Fire Emblems had amazing animations. I can’t think of many 2d sprite based games that have gorgeous animations like the Super Robot Series get. Although this series is very numerous and I would treat it like Fast Food or Food outings. Really enjoyable when you have it. Can overstay their welcome if you play them too much or too long.
Project X Zone Series (1 and 2)
Another Bamco tactical RPG. This one is a funny crossover between mainly Namco and Capcom, however notably the 2nd entry adds Nintendo too with a Chrom/Lucina addition and Fiora from Xenoblade. Similar to the SRW series, it has nice animations and nonsensical plots (required for crossovers :p), and also can feel like it drags on a bit too like the SRW series and be a bit too much for long periods or too much of.
SD Gundam G Generation Series (mainly the DS ones)
I’ve only played a few of these, but I have a strong fondness for the DS ones G Generations especially SD Gundam G Generation DS (which is sort of a remake of the Monoeyes one for the Wonderswan (earliest depiction of the Seed Series)) with its original character side plot for the Monoeye Gundams being a favourite of mine and its 2 branching paths (one gives you a pre dominantly UC timeline cast the other gives you a predominantly AU (Wing, X, G, Seed) cast and a secret path that gives you a weird mash of alt universe heroic characters and villains). The other one I mainly played was the Cross Drive title which had more features and better representation from the Gundam titles, however didn’t have the Monoeye side story or it’s characters. I have also played the Cross Rays title on Steam, but didn’t enjoy it as much because, I tended to enjoy this series on handheld (same with SRW) vs a PC.
Of note, aside from XCOM and Symphony of War. I tend to prefer my SRPGs or Tactical RPGs on handheld for some reason. Of course the exception goes to FE Emulation for romhacks and the Tellius entries for Fire Emblem (FE9 is probably my personal favourite FE).
As for features I’d like to see incorporated in FE? I like FE for being FE vs some these other titles (which I like them for being them). I’m not sure I can nitpick anything in particular, but something I want to see executed better in FE is the depiction of scale.
Depending on the nature of the storyline, say for FE 7, the main cast party feels just like that, an adventuring band where every character is their own singular unit acting kind of like and elite hit squad. Whereas, aside from the pre route split and early revelation missions, it feels like in Fates your units should be more of a representative of like a squad of units (which it actually looks like in the route split battle (when you enter the battle animations, you see admittedly not great background units going to war) because you feel like an army going to war.
Three Houses battalions kinda make it feel a little better visually and does suit it’s war storyline post timeskip, but it didn’t quite look right. Even if something like that wouldn’t have a gameplay affect, it would be a cool visual to see (think units density scales with HP like in Advance Wars). Of course your hero character cast still lead and are stats that they scale off.