Bloodmoon has a completely different feel and tone than Morrowind (or for you folks who worry about these kinds of things, the island of Vvardenfell in the Morrowind Province), which is extremely refreshing after hours spent in the tribal wastelands and swampy coasts. After the fanciful culture and creatures in Vvardenfell, Solstheim's real animals and realistic area and buildings hit closer to home. Home being this world we live in. Taking you character from a make believe world into something so real (and I'm not talking graphics) makes what you do seem more important and the enemies more menacing and the people deeper, even though they really aren't.
I won't give any spoilers, but take my word that even the bosses are better because they are their own characters. They aren't just a stronger version of the same things all around them. They have motives for what they do that you learn through the quests and encounters with them, and are not just told that they are smugglers that need to be killed or an outlaw that has killed a friend of your employer or an evil deadra. Morrowind only has one of these kinds of bosses, whereas Bloodmoon has many.
The new weapons and armor are truly awesome. Powerful weapons and armor can be found there. Relatively great armor can be bought without questing, and the weapons you quest for are some of the best in the game.
Quests are difficult and they aren't all just going out and killing someone or retrieving an item or escorting an NPC.
My favorite part of what Bloodmoon and Tribunal both offer that I am willing to tell you so as not to spoil anything is that you are able to participate in a few battles. Not all one on one or one on multiple, you can fight alongside many friends against a great many foes that you would not defeat alone. This is a truly great expansion that is worth more than it costs.
