I don't think they're being slammed for being "too technical". I think they're being slammed for being technical, and nothing else. Writing a song, should be about the song first, and the artist's technical prowess second (or third). In listening to Meshuggah, they sound like they care more about flouting convention than writing quality songs. I like a good number of technical bands. Zero Hour would probably be the most technical of those I listen to with great frequency. But I think Zero Hour does it right. They play with great skill, but also write songs that I want to hear with regularity. I think the biggest difference may be the vocalists. Zero Hour use a melodic singer, while Meshuggah opt for Death vox. The latter fail to inject any melody into the music, and as such, it just comes across as unlistenable.
To me, the real challenge for a technical band should be to write a track as technical as possible, while still operating in the framework of a memorable song. Meshuggah's completele disregard the second part of this equation leaves their music completely pointless to my ears.
By the way, did Meshuggah actually set out to write a song that was 33 minutes in duration? If so, that's about the lamest thing I've ever heard.
Zod