The lack of a demo isn't what's driving me away, it's that everything here's being set up for a disappointment. Disregarding that I've played, finished, and been disappointed by a rented console version in the time I was waiting to buy a PC version: a port should not take that long to make when full games have been rushed out faster. If it is, it should have significant improvements...with the delays, I was thinking something along the lines of the Lost Chapters, which is something that could really make the game worth playing, not a few new weapons. Upping the difficulty is a good start, but it doesn't change the abrupt and underwhelming ending like an expanded game would. It had so much potential, then wasted it away at the last moment...this is EXACTLY where an expansion is needed.
Paid DLC for trivial things that should be included anyway, like Black Dye (come one, that's bound to be the most used) is a sign of greed. The long production time with minimal additions is a sign of laziness. A lack of a demo is a sign of faithlessness. Overall, it looks like it's intended to trick people more than reward them. The only way this is worth buying to me is if it's on major discount or if the mod community really flourishes.
Qualifier: From what I've seen, the port does look well done. But the point remains that more is expected from this time-frame.