IIRC Donaldson carried the tag of a promising youngster for some time while having to endure a series of long-term injuries, not unlike Stevie Ward. He's not a giant but I reckon there's a good player in there, and I hope he'll repay Leeds for granting him a longer deal.
Even in the glory days we needed players like Kirke, Clarkson, Mathiou etc to spell some of the better forwards; all clubs need players like this, and I actually think Donaldson has better attitude, technique and skill-set than most.
We already have class players for Donaldson to complement, in Merrin, Ward, and Martin. That said Ava could do with a better front row partner than Singleton/Peteru/Cuthbertson, not to mention a decent hooker... We're investing a lot in Crosby, let's hope he's worth it next season.