It's open to debate.

I had hoped to be honest, to see more wonders, especially a few fortress exclusives for units.

The only way to solve that issue would be to make a higher proportion of the wonders late-game wonders (ex: near the refined technology or right before them).

That would make it a bit less of a race.

There are other issues that it solves. The first is that the starting city's resources and environment have a very substantial effect on your early game progress. Later = starting is less significant, as are larger maps.

I guess I've never given it much thought. I often build Ereog's tower in a fortress or even a town because the research and mana producing buildings are usually a priority for me. I've never felt like it didn't fit that I was able to build them in non-conclaves, same thing with the towers that lead to the spell of making. I guess the justification in my head was always that these are major works of your civ and not buildings that are specific to a magic/knowledge based city. In fact, I find it much more odd that some of the 1/faction buildings like university are not city-type specific.

I suppose that's true to an extent, though I've never really liked the idea of the wonder that anyone can build until someone has built it anyways. I've always much preferred the Age of Empires and Age of Mythology take on wonders, where it's a pretty building determined by the faction you're playing and can be produced by anyone who wants to put the resources into making it assuming that they have the correct culture to build the specific wonder, to the Civilizations take on wonders where they're globally unique structures that provide bonuses (some of which are quite significant) and don't even vary based on the culture which produced them. Beyond that, I don't really feel that the race to the wonders really adds anything interesting to the game; all it really does is encourage players to pick out the 'optimal' tech paths to gain access to the wonders and have at least one high-production city to rush it to completion (in E:FE:LH, you don't need the high-production city, but I don't really see that as a great improvement, and given the bonuses that the higher-difficulty computer factions receive, all that this really means is that the human player won't have any wonders unless taken by force when playing the higher difficulty levels). One thing that I do feel that Civilizations II did better than AoE/AoM is that wonders were irreplaceable if destroyed; after all, we have this structure which is supposedly so unique that only one of them can be built at a time, but isn't so unique that we can't build the same thing over again as soon as the previous one burns down (although it's also arguable that the replacements could be a lesser reproduction or a new structure designed to replace what was lost but not necessarily reproduce it and we just can't tell because there's a limit to how much detail you can put into a game).

I'd much rather see wonders turned into a way to make the various factions more different from one another than to see the game continue with the silly race to research or construct a specific building. If I want to build pyramids and I have the resources to do it, then it shouldn't matter that someone else already built pyramids; what should matter is if the culture of whatever faction I'm playing allows for pyramids or not, because it's cultural differences that determine whether or not something like that is built, not the question of whether or not someone else already built something similar.

Of course, it's also harder to come up with a set of unique and relatively balanced wonders which help to differentiate the various factions than it is to come up with a single set of wonders for everyone to use, which I rather suspect is a large part of why this isn't typically done. In E:FE:LH, I'd at the least want the wonders to be kingdom-specific or empire-specific, with the bonuses designed to help show the differences between the two alignments, but it's probably too late for that, outside of heavy modding.

As far as Ereog's Tower goes, I tend to agree with davrovana - it's a rather underwhelming structure, especially when you consider that the 1 per faction Forge of the Overlord towers give you a shard mana for a couple different shards as opposed to Ereog's single air mana, and Ereog's Tower doesn't have anything else worthwhile going for it (unless you're going for a henchman or sion build, as those are the only things that +1 fame per turn are useful for at the point when Ereog's Tower is likely to come into play, but there are easier ways to get that bonus). I also agree with perigrine23 that if Ereog's Tower were restricted to Conclaves, well, I'd much rather build the mana and research structures in my Conclaves before getting to Ereog's Tower.

What about +1 Air, +3 mana/turn, +1 Fame/turn, and unlocks some kind of spell? Windwalk: All units under your control increase movement by 1

Not sure.. the AI tend to build Hosten's Library very very fast. And that wonder is in the end of tech tree.... If the AIs actually raced for any of the wonders humans would never get even one built at all :3 Another one is the Bazaar wonder. It will be gone very fast.

So i've learned to beeline for the specific wonders that AIs ignore lest let the AI wonderhog some more while giving me none making the game even more unfun. I could get the bazaar wonder but i will have to give up on the giant windmill and I'm not willing to do that for a fortress city of mine.

And I only have built hosten's library like.. two times ever.