Fans have waited a year to watch GoT. So I don't think waiting 5 weeks for Episode 5 will be a big deal. A lot of people also watch it because they don't spoilers to ruin it for them. I have friends who wait for each Season to end to watch it in a spree but it always ends up getting spoiled. My cousin is waiting for the entire series to end so she can binge it all at once, but unfortunately through spoilers alone she already knows most of the major plot surprises (which are the backbone of the show), like the Red Wedding, the Dragons, the Oberyn-Mountain duel and what happened to Ned Stark.
Waiting for a new beginning is kind of easier to deal with than waiting for the continuation of something that's already begun (or at least, that's how it's always been in my personal experience). I'm relatively safe from spoilers though because my age group isn't really the target audience, and so not a lot of people have watched it. There are still quite a few, but their discussions about it don't get past the usual "it's really graphic in terms of sex and violence" and how the show has the tendency to kill off some characters that you grow quite fond of (something that's been repeatedly said on the internet since the homo sapiens sapiens emerged). I also make it a point to say "dude don't talk about it with me or around me because I'm planning to watch it in the future" whenever they ask me if I've watched it.
I've heard a lot of complaints from long time fans of the book about how the book is never going to be finished and many speculations stating that George might have written himself in a corner or something along those lines. If the movie decides to go with their route but making the same point (like you said) and end it first before the book does, or if the book ever finishes assuring everyone that the TV show now has enough source material to finish too, then that's really the only time where I'd start watching the series.
