Oh, look it's the holiday season, so I'll resist flaming! You can thank me later!
Yes, if you want more luxurious redemption choices with room upgrades for that special stay, IHG is most definitely not your man! Hilton, Marriott and SPG all promise space-available upgrades and it matters not whether your stay is paid or redemption. And all have a wider range of properties you truly want to spend leisure time at!
Having said that, I've found IHG to be an excellent back-up to Marriott. Here in the UK, whilst Marriott has good coverage it's not nearly as omnipresent as IHG, indeed IHG has more hotels in Greater London than Marriott has across the U.K.
I prefer Marriotts, but nothing beats IHGs earn-and-burn rate. Marriott's earn and burn currently runs at about 50%, IHG is nearer 80%. So, no, the IHG scheme is far from worthless, indeed as a free-stay rewards program at Spire level it provides the best bang for your buck!
But I do agree, the no upgrades on redemption stays rule is daft. So the reward for staying at IHGs is a dumpster view unrefurbished room... that doesn't really give warm feelings about IHG. But I don't play IHG for romantic redemptions. I use them on airport, visiting family, lads weekends and activity stays, where what I need is a convenient clean hotel room close to my activity. Then I don't care about the upgrade... mind you, I've had some very tidy redemption upgrades as many IHGs choose to go above and beyond, worth mentioning are DC HI (Suite); Oakville HI, ON (family stays with room upgrades and free breakfast for all); Milton Keynes HI, UK (Suite); Prague and Amsterdam CPs (larger rooms).