Henry is a legit draw, Smackdown ratings were up with him as champ lol.
A draw is impossible to decipher and that it's biggest problem, some people use it as ratings only,some mention merchandise sales making someone a draw, some use outside interest as a draw, some will mention crowd reactions as an indication of who's a draw and some use a mix. Usually it's used in a way of I dislike this guy and this a reason why from what I've seen ( I think we touched on this before about Double J D'Z)
It's also hard nowadays to tell just how much the audience is drawn to a WWE event because of brand name. Wrestlemania is similar - it's obviously a bigger spectacle than it's ever been and can sell several hundred thousands buys just by being WM. But at the same time it does over a million buys every year, pretty much every other PPV (except the Rumble, which has the Rumble match and a brand name in itself) does just over 200,000 or below buys, no matter what the card is. This is met with rare exceptions.
I'd say crowd reaction is important but the least important. Most midcard guys from just about any era are over with the crowd. Some more than others. But at the same time they're over with the crowd, the ratings might be going down for their matches. There was also a topic on here not long ago about how a lot of guys might get apathetic reactions from the crowd but yet still draw fair ratings and do very well in merch sales. There's also been events that have done great business but the ratings leading up to it are pretty average. Wrestlemania 28 being an example, though WM bucks the trends as previously mentioned. But the logic is still the same.
Even though it is telling when you have guys drawing in a certain number of people week after week after week (or causing the show to lose viewers week after week after week), I'd say gate attendance and the number of buys a PPV gets with you as the headline is an indication if you really are a top draw or a draw in any way.