Most of your maps are quite interesting and unique, so I'd definitely like to see them improved
Besieged: I've never played it. The idea is interesting but I can't judge whether it works or not. You could improve it by adding stone to all the watch towers at the start of the game (using the new command !ADD_WARE_TO that we added in the Remake) and also move all those weapons from the storehouse to the barracks, so your serfs aren't moving them across for the first few hours of the game (unless that was your intention?). The Remake allows you to put more than 255 weapons in the barracks.
Blitzkrieg: I really like the visuals of this map (especially the narrow bridges across the chasm). I like the way you've chosen a few terrain types and used only them, instead of trying to put every terrain type on one map. I did play this once although it was during an RC test against some inexperienced players, so it wasn't really a proper game. I would say that having players so close doesn't work so well, there's not much space to build both of your villages and you end up with a very long narrow village leading up to the iron. In my opinion the iron hills would look better if you made them out of the richest iron tile (like the original maps mostly do), rather than a mixture of iron tiles. Another thing: There's basically no space for farms and building amongst the trees is hard.
Borderlands: I've never played it but it looks like an interesting map. I think the terrain could be improved, look at
this image for a suggestion on how to improve your coal. Another thing to consider is that the bottom players have their stone below them so their stonemason needs to walk a long way around the hill, since he'll only mine from the bottom. There's also large areas of uninteresting grass, look at some of The Dark Lord's maps (and the originals) for ideas on how to make grassy areas interesting (which is one of the hardest things about making KaM maps). I also don't like seeing dark green trees mixed with other types of trees, I think they look best on their own (that's how it mostly is in the original maps)
Horseshoe: This map seems to be pretty popular, I often see people playing it. Once again the grass is a bit uninteresting and the beach really needs some of those dead shrubs you see on the tutorial beach, as well as crabs!

The elevation at the edges of the dividing iron hill in the middle look a bit strange at places, you may need to edit it in the Remake editor as it can look a bit different in Krom's editor depending on what graphics card you have. Some areas of the beach are too steep to walk on and some areas of the map are too steep to build on (use canWalk/canBuild in the Remake editor to see this). The player on the right seems to suffer from more of this.
Oasis Struggle: IMO this map is really too small for 8 players, I think it would be better for 4 players. I have played it once and it was kind of fun, although we lost quickly, perhaps due to the fact you can't build towers (was that intentional or just because there's no stone?). I remember struggling to find space for woodcutters with two players at each location. The location in the top right has 40 less gold than the others

(use the Remake editor to see resource numbers)
The Tyrant: I haven't played it so I don't know whether it's balanced. 1vs2 is difficult to balance because the 1 player must be twice as powerful as the others. The bonus of iron and extra starting resources should be enough to balance this, but it would need thorough testing to really decide if it's balanced. I quite like the terrain, I think you could make the iron hills look better and the edges of the coal more smooth/gradual.