Let's simulate the actual result of your HD idea as a brief 1 act play I wrote.
Relic: Hey we've applied some balance fixes and new HD graphics to vCoH and you can buy it now for $30! Great news!
Community: So you fixed a few bugs that you should have fixed five years ago and took the community's balance suggestions and are charging $30 for it? Relic sucks. SEGA sucks. You suck. Fire Noun he's a dirtbag!
Relic: But new graphics.
Community: We don't care about graphics, these new graphics aren't as good as the old ones. The graphics make the game run slower on my machine.
Relic: But you asked for this.
Community: Nobody asked to pay $30 for a game we already own.
Even if everyone on COH2.ORG loved it and bought 10 copies we'd still be hundreds of thousands of copies short of even breaking even on something like this.
We feel that it's better to support our current players who already bought CoH, rather than to close it and try to make them buy CoH 2015.
without bugs and staghound fix i would buy the new version for 30$