The reason I've been quiet/inactive here is due to playing Sacred. The storyline and general setting/world is much more advanced than DII...there's more it's more of a RPG than DII in that sense.
The skill system needs tweaking, as mentioned before. In theory, the concept is very nice and could be well balanced. Think of it as playing a DII character where all skills are timered, but where with skills/stats you can bring down the regen time...but increasing the skill also increases the regen.
It's a system that I like but that right now isn't balanced. Some skills (although fun/cool/nice) you won't ever use, due to the regen time. Some skills you'll just pump to max (Summon Woodland Companion...a Valkyrie sort of) since regen time is irrelevant. Most skills you use will sit at level 1 for a very long time though.
One of the biggest flaws: the very limited amount of skills slots. You start with 1 skill slot and gain a few, maxing out at 5 slots eventually. Think of a skill slot as a hotkey for a skill in DII. Now in DII, alot of builds can go by utilizing no more than 4 skills...but in that number you'll also have to figure (pre-)buff skills. Try casting buffs by not using a hotkey but instead by clicking on the right skill icon and selecting the skill, casting it, then switching back in the same manner. This should make it clear why a great number of skills in Sacred are never used by players...they're simply not good enough to justify having in a skill slot and switching is too much of a hassle. In my opinion, Ascaron should double the skill slots, that should fix the problem and get players to actually use those skills.
Equipment is alot more fun than in DII...graphs are much nicer and you'll actually see each piece of equipment change your appearance. However the distinction between item types/rarities is quite vague at the moment. Also mods on items need some tweaking.
Bugs....there's plenty of them, but personally, I've experienced only a few...almost exclusively random side-quest not triggering correctly. Nothing game-stopping, nothing big. In the current patch, game-stopping bugs should be extinct and there's still alot of work being done. But Ascaron is really active when it comes to bug-fixing/patching...more than any other company I've seen before. Yes the game should have been alot less buggy when released, but we all know how games are push onto the market nowadays...at least this company is trying to fix things that they missed due to release deadlines.
Monsters are alot cooler than DII monsters...big monsters are big and not like semi-big like the act bosses in DII. Your average Orge compares to Andariel size and you should be able to guess how much bigger Giants are than you. Did I mention the Dragons yet? The first time I ran into a Dragon I was dead before I had it totally on my screen. And you have a bigger area of view than in DII. Also there's flying monsters that'll actually swoop down and breath fire down on you and that likes. Lots cooler than the 'flying' monsters in DII.
Character animation isn't as good as in DII though. Walking/running for some classes just doesn't feel right...it's not quite smooth/fluent. Bit hard to explain but it just doesn't feel natural for some characters. Overal graphical quality if of course alot better, nothing strange considering the fact that DII was released years ago.
Overall, I think the game is well worth the money. Right now it's not as good as DII yet, but it could very well get there. And it sure is a nice break from DII for me (I'm getting to the point where DII doesn't have to offer me much anymore).