My point is not necessarily that you have to capital-I "Innovate", and certainly not just for the sake of innovating -- Its more that I think one needs to go into an endeavor like this with an open attitude about what might really need to change for the better, not just superficial things, but more central things as well. And not just things that might really need to change, but also things that might be changed to make a game that's substantially different than what's come before it but still capture the essence of the games that inspire it. Challenge the assumptions; if the assumptions are true, let them stand, but you can't know without first asking the question.
If you're making a game to scratch your own nostalgia, then fine, accept that it will have limited appeal to yourself and others who are similarly nostalgic. But nostalgia itself cannot appeal to new players -- if the mechanics you remember fondly are strong they will appeal to new players, but if they appear limited or outdated to anyone who lacks the reference point of the original games, they won't -- younger gamers today grew up with different expectations. Their generation views NES games not much differently than I view Pong or early Atari games -- that is, not very appealing from a player's standpoint, and not from an aesthetics standpoint alone, although that's part of it--because the scope of what I'm accustomed to being able to do in a modern game is so much different than the scope of those older games.
You also have to be aware of what the competitive landscape is today -- there may not be any WC2-likes on the market (I think, more likely, there are and they simply go unloved for the reasons I mention) but there certainly are 10s of small-to-medium-sized games that fit into the RTS umbrella genre, most of which are reasonably polished and are free, freemium, or inexpensive to buy. Regardless of whether any other offerings compete in however narrowly a niche you'd like to carve out, you're still competing for those same eyeballs and dollars. That's why I'm saying that its more important to create a great game than to hold unflinchingly to the tropes of the past.