We'll be revisiting how we indicate questions with watched tags next year. As we've been releasing the updated themes over the last six months, this concern was repeated on several sites. The pale yellow is difficult to see for some users, and particularly on some sites where the question background isn't white, like the cream used on English Language & Usage:
I've got great color vision and I can barely tell which is which.
What this really tells us is what experts in accessibility already know:
Color isn't the best way to indicate... anything.
At least, not on its own. So, we're going to be reworking how we indicate watched tags when we look at accessibility early next year. I'm not sure what it's going to look like at this point but it will be either moving away from color entirely or adding something so that it's not color alone.