I think you and I have different views of the front page feature. It's not simply meant to be a catalog of the most awesome MOCs. Instead it is meant to be something new to look at on a rotating basis that will bring people to the front page, based on things that caught my (or another admin's) eye. It's not quite like a blog, though, because I always contact the builder first for permission and for some information, and then I have to edit the photo, which can take a while (especially with larger MOCs). So it's not often the lastes big thing. I tend to have a backlog of people I've contacted but who's MOCs haven't been posted yet (including yours, btw).
As to the MOCs I post, I think they're all high quality, but if you look through the archive you'll see that they vary greatly - it's not just all huge layouts of giant castles. I also do small things like microscale, vigs and customized figs, medium things like this, and of course larger scale MOCs. I try and mix in some less traditional things now and then like a sculpture or a miniland-scale figure. I also don't keep going back to the same people. It would be quite easy to just post everything from a short list of top MOCers, but I'd rather bring in some variety. Indeed, I give some preference to people outside the CC community - I figure that most CCers have already seen the last castle by MrTS, DARKspawn, Jens etc (just to pick some past CCC winners) - but maybe not from a czech builder who doesn't post on English-language forums. I want to use this as a means to encourage all AFOLs to build castle, not just to reconize those at the top of the craft.
Turning to this tower, I do think it's a perfectly balanced MOC. It uses a number of different techniques - the shape, the arrow slits, the stonework - admittedly most pioneered by other people, but it puts them together quite well. The roof, though, is very well done and I'd not seen that done so well before (you also commented on the roof on Flickr). The evolution of this MOC was very interesting to watch, and some nice techniques were tried and subsequently discarded (the earlier crenellation). Finally, this was a first castle MOC, which is particularly striking given the skill displayed.
On the name, yes, I agree. This is not a castle but more of a watchtower. But I go with the names people use for their own MOCs.