This is probably the most interesting of the PHB dinosaurs. Good physical stats, four natural weapons, high speed, some natural armor, huge skill bonuses and pounce on top of it all. All this is available for four RHD.
However, I still do not think deinonychuses need a positive LA. A typical orc lion totem barbarian will have more BAB (and therefore better Power Attack), equal strength when raging, and out-of-combat options ranging from Trapkiller to skills. +0 LA.
[insert scientific indignation on the classification of elasmosauruses as dinosaurs here]
Sure, Huge size with 26 strength is worth something, but when one has only one natural attack and moves as fast as a gnome melee gets less interesting. 10 animal RHD only worsen the deal. -0 LA.
The big brother of the deinonychus... except one could just advance a deinonychus to 8 RHD and get better stats for the same price. -0 LA.
Yes, the stats are high, but we're talking ECL 16 here. Even fighters could already be throwing planets around by now. -0 LA.
I'm sure there's plenty of CR 18 monsters to grapple or bite, but I'm not finding any. -0 LA.
Next up: dire animals. I foresee more -0 LA's.