You have to remember that the first two games are quite old now, 1996 and 2000 respectively. There is a large amount of new gamers who will know the name, will have missed the first two, and would much rather have a new version than play the old ones.
The brand value of the Diablo name is very big, the games were popular in their time and those that write about games now will have played them and therefore their enthusiasm will carry over into their writing and add to the hype.

Apart from the Original 3 Warcraft's, I Dislike the other games by Blizzard - So anything Diablo (Couldn't Play either for more than Five minutes) or any other Starcaft (i have never Finished any of the Originals Campaign) is an instant Do not Buy from me

Well from what I recall reading it has coop, that coupled with a solid if uninspiring game (assuming they stay true to the previous games) will probably be enough to make me get it when its cheap (which will be easy since I won't have a computer capable of running it for a few years at the rate I'm saving). I've tried all of blizzards major games aside from WoW and they've all felt rather dull and uninspired but diablo was just fun enough that I could play it whereas the 'craft's bored me shitless

Actually, it was something that Blizzard themselves commented on. They originally had a much more neutral colour palette, thought something was wrong, replayed Diablo 2 then changed the colour palette accordingly.
The size of the changes have nothing to do with it. It's the mentality behind those changes and the impact those changes have. Yes, altering the colour palette is a minor change and should have a very limited effect on people's enjoyment. But making the change simply to make it 'more Diablo 2' in appearance is the wrong thing to do.
Look at the feedback they've received from their fans regarding those changes. There were even people who went as far as to recolour the videos to show how they think it should have looked. Trying to please a fanbase of an old game by making the new one as similar as possible fails time and time again. You need a completely fresh approach. Which is what they had initially and it worked better too.

I don't think they ever had a fresh approach. The game appears to play exactly like the previous games, with the changes being cosmetic for the most part (3D, possible colour changes, potions removed).
They're catering for the fanboys because there are plenty of people still playing Diablo 2 on Battle.net. They want all these people to buy D3, so will make and market their game accordingly. Their other key market is pulling in WOW players.
They appear to be doing something similar with Starcraft 2, which to my untrained eye looks just like a graphically updated version of starcraft.

It just looks like Diablo 2 rendered in watercolors, and I am NOT playing Diablo 2 again. It wasn't even very good the first time.

Indeed - though I've seen very little of D3 (that is, less than SC2), both do seem to be very much their respective predecessor in 3D. And that's one of the reasons I'll be buying both of them.
I do enjoy the Diablo series' arcade hack-and-slash simplicity, but if it does get an upgrade in its storytelling (with side quests, more choices in dialogue, in-game cinematics, etc), that's not a bad thing as the story is what I feel has been lacking (even though it deviates a bit from said arcade simplicity).
Starcraft has better storytelling, but anything to make that even better is a good thing in my book (up-close-and-personal shots, in-game cinematics, less of the talking heads and more interaction between the characters in the briefing room... yeah), also the less-linearity should be interesting to see.

I don't think you get what I mean. I'm saying that the game is very similar to the prequel. More similar than it used to be. More similar than it should be. More similar than many fans are comfortable with.

You're right, I don't think I get what you mean. I wasn't aware that many fans had a problem with D3, and I for one wouldn't want the formula changed by much.

Where are these many fans?
What you're saying here is that it's more similar than you are comfortable with. The last statement has no backing and is added purely for dramatic value.

The involvement on Leonard Boyarsky is a good enough reason for me. Also, the new features like respecs, skill runes, and random generated adventures sound neat. I found D2 rather boring, actually, so hopefully D3 is less grindy.

Anyone here still playing D2 on bnet?
I started again a few days ago, determined by all the D3 ruckus and I'm almost through with normal mode.

i did that about 6 months ago... played a barb up to like level 30 and got bored with it again.

Me, i've a sorceress wich i play sometimes. (screenshot below)