While being mostly a metalhead, I'm all about great songs first and foremost, regardless if they're fast or slow.
Take Nightwish for example, their album Imaginaerum - it has a jazz song (Slow, Love, Slow) that has nothing to do with the rest of the album or their entire discography but it's so damn good that I like it. It will be the same with the new album, if there are many slower songs and they're all great, so be it! I look forward the most to the WTF moments, the tango / swingjazz stuff, the bagpipes, all the crazy insanity that I love to find here and there in records (another example, Unia from Sonata Arctica... a total mindfuck of an album, many hate it, I consider it one of their very best. Sometimes with an estabilished band it's fun to just not know what's coming next).