Personally this genre doesn't fit me because there's a detachment between my actions and my player, it feels like I'm commanding the player character instead of becoming immersed so 'I am the character' as you may find in either of the aforementioned RPGs both of which I've played 100s of hours. In other words, it doesn't feel like I have much skill if I hit the hotkey to deal a tonne of damage, hit block to block compared to having full control over movement and executing complex or risky dodges. Therefore I feel no satisfaction in defeating my enemy, it feels more like I put in enough time to get the right levels and equipment to beat said enemy instead of I use my skill and executed my attacks/dodge/blocks well in that fight and won because of it (Skyrim melee holds no reward for the same reason for me, but I can use archery to feel in total control).
I'm playing as a Wizard and I'm find their is actually more strategy involved (so far) in D3 than D2. Particularly playing Solo, I'm finding I have to prioritise which enemies to kill first, keeping my distance away, guiding enemies into choke points to maximise my AOE damage, etc.
I haven't played the other classes yet so I don't know how it compares, but when I enter a room with 30 guys and manage to defeat them all using a specific combination of spells then I really get that sense of satisfaction, cause it's actually quite difficult.
At this stage if I just spam spells with no thought I will just die, and die quite quickly.
It's definately lots more fun playing in a party though, it is where the game truely shines. I think I've played 12 or so hours now, 10 of which in a party with mates and had a complete blast. It allows you to create a synergy between players really well. I've been playing with another Wizard and a Barb, and without even consulting each other, we ended up in this game style where the barb goes up front and tanks damage, the other wizard issues freeze spells and tries to take out the hard guys, and I issue AOE spells and knock backs to stop everyone from dieing if things get rough.
One other thing I'm actually growing into the skill system, I really disliked it at first as I thought it would impeded personallisation. But again, the other wizards I play with are all around the same level as me, but all of them play the class differently with different go-to skills and different equipment loadouts, based on how we each like to play. Perhaps later on their will be a specific 'best' or 'easiest' way to play each class, but so far the apparent variation is very pleasing to me.
The game is also
incredibly polished. Other than the login issues (Which I actually haven't encountered once), I haven't had one missed frame or glitched area. My game has never crashed. All the voice acting is beautifully done. NPCs aren't going around talking into walls. All quests have worked 100%, etc. It really is commendable on Blizzards part.
I think Diablo 3 looks great, very smooth and the special effects are awesome. None of the zones really show anything off in the Beta. Once you get past the Skeleton King the game opens up a little more. I absolutely love the morbid dungeons with all the fire/lava racks, torturing devices. Boss fights and events get increasingly more fun and require some some strategy. 
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