My problem with the Blade ending is more a problem with the type of ending they used than with the ending itself. The ending was dramatic and heartbreaking, I'm not denying it, but I feel that the "great sacrifice for all mankind" endings are overused in TV shows in general, if not Kamen Rider specifically. I mean you could argue that "Oh it's a testament to their development that they realize the safety of all outweighs their own happiness and any other way is just selfish" but to me the Greek tragedy thing just seems like a cop out to attract viewers rather than a successful resolution to a story we spent so much time watching.
I guess what I'm trying to say is that the type of ending used in Blade was so overdone (poorly in American TV) that it gives me a feeling of disdain.
Ending aside, the rest of the series was pretty good. I liked the playing card concept and the suit designs were interesting. Actually, I would have to say I liked everything about Blade except the ending.