Welp, got my first ToME win. Despite 2 deaths I kinda wish I had played on Nightmare instead. Summoners are too strong for normal.
Some thoughts on the game:
+Lots of classes and races to try out. This is the best aspect of the game IMO - trying out new classes and race combinations
+At first I hated the idea of a cooldown system in a roguelike. If I wanted cooldowns I would play shitty WoW am I rite? But after playing the game I've grown to like it. On top of managing your normal ability resource (stamina, mana, equilibrium, whatever) you also have to plan around the fact that your abilities take time to become available again. Sometimes you will get support abilities that can reset or reduce the cooldowns of other abilities. Having to manage cooldowns adds much appreciated depth to the gameplay.
+By the midgame you have a good variety of abilities from your talents & items, plenty of options to choose from in combat
+No Nethack-style gotcha deaths, always a plus
+Passable graphics & music for a RL
-Danger level of most enemies is fairly low. Compare to Crawl where enemies are generally less numerous but more dangerous. Too much of the combat in ToME feels like trash combat, even for classes that aren't summoner-level strong... Upping the difficulty level could alleviate this issue but doing so would probably exacerbate the next problem
-Randomly generated uniques. Most of my deaths in ToME come from these. Unlike actual Boss enemies, these assholes more often than not are just buffed trash enemies. Sometimes however the RNG decides to dump some absurdly strong unique on your head and you are dead before you even know what happened. Yeah I know, inspect everything you see. Except as the game goes on and enemies are loaded down with more and more talents it can be difficult to tell how dangerous an enemy really is just from glancing at the stat pages. Random uniques are ToME's 'gotcha' deaths.
-The game is too long IMO. The early game is lame. Even if you skip optional zones (which would leave the player underpowered and could make the endgame too difficult for weaker char types) there are still a lot of dungeon floors to clear in ToME... Despite my desire to try more classes and races I won't be replaying ToME anytime soon due to this. The Crawl style of a relatively short core game and a whole optional 'extended' game on top of that for players seeking extra glory is more to my liking. And due to this & the problem of uber-uniques, I will never, ever, ever be playing ToME on roguelike mode 
-Extension of previous problem - for a game this long the enemy variety is too low. Enemies you first meet very early in the game will continue to reappear until the very end. I was disappointed to see nothing new even in the end dungeon. More orcs & demons that I've been fighting for half the game, more undead that I have been seeing since level 5, more snakes, more drakes, more bone golems, yay... FFS, give me some ancient liches, some orbs of fire, some killer klowns!
-Wands, scrolls, potions... Although you will have a large number of abilities available to you by the midgame in ToME and I like that darkgod tried to do something new by removing consumables entirely, I find I miss the added variety and resource management aspect that consumables add to Crawl and most other RLs 
-/+Unlock system, on the one hand it gives players goals to work towards, but on the other hand having unlockable shit in a roguelike seems like borderline blasphemy to me
It's not a bad roguelike. In fact I think ToME is a great choice for any poor soul that is looking to play his or her first roguelike. I will be giving it another spin someday. For me though, Crawl is still the king.
Also if I hadn't seen someone outside the game mention it, I would have had no idea that you can
close the 4 portals in the final fight.
Is there no message or hint in game that informs you of this? Or did I just miss it?
For the last point, there are fairly simple ways to unlock everything all at once. It gets quoted every once in a while in the thread, and I forget the exact method, but I saw it a few pages back.
As for your other negatives, I tend to agree on a lot of them. Recently I've been using the Everythings a Boss mod, exact name slips my mind as well, which basically turns everything into the super uniques you complained about. This is, nominally, a Bad Idea, except you get an ungodly amount of loot, such that its not unusual to finish the second dungeon and be entirely decked out in artifacts, barring a few of the harder slots to fill.
Honestly. My biggest issue with the game is the stats and the stat screen. Talents are fairly easy to figure out, but, how much spell power you need vs enemies saves, and at what point is a save good enough. These things feel like they are hidden away, and it would be nice if it was a little more transparent. But maybe I just have no idea where to look.