I agree with you 100%. I think GM is allowing Caddy to benefit the SRX with the 3.6L V6 for 2012, and the Terrain/Equinox will dump the 3.0L V6 for 2013 and have the 3.6L V6 in its place (like ocnblu already stated a few posts up). Honestly, I would wait another year for the 3.6L V6 engine to be the upgraded engine option (though if the 2.5L 4cyl is a vast improvement over the 2.4L 4cyl, maybe I'd consider that) for me to consider a lease option. I don't want a Denali version just to get a 3.6L V6 though; however, it could have that as the only engine available.
dfelt, I'm not sure I'd want to see the Typhoon name return (and boy do I LOVE the original Syclone/Typhoon). I think the Denali name would suffice for what you propose to be a Terrain Tyhoon (btw, isn't a Terrain Typhoon called a Tornado? ). I still think GMC should offer the normal packages (W/T-SL, SLE, SLT) in addition to the Denali luxury and and All-Terrain off-road packages. Then GM could restyle the Hummer Hx Concept as a GMC Jimmy offering to compete with the Jeep Wrangler & Toyota FJ Cruiser, and I'd love to see an All-Terrain version of the Terrain (if possible, which I believe PCS/Oracle once said the Theta platform could be made into a beefier 4WD - a'la Jeep Patriot). Giving GMC those model packages could differentiate them enough from their Chevy counterparts (assuming the General doesn't give Chevy the same stuff).
Anyway, I hope the 3.6L V6 engine is offered on the 2013 Terrains, and a slight MCE too would be nice (but not necessary).