Yes, I agree with Frostyboy - the War Hydra is not very useful at the moment. Cold One Riders are better IMO, being as easy to reasearch adn having better defence and speed, and being cheaper too. I really like the Hydra graphic so I still build a few - but mostly it's better to churn out the Cold One Riders. I can see that on Random Maps the Hydra could be very useful for Dark Elves with no Raptors, but on the Warhammer World map the Hydra is rather redundant.
+2 HP would make it more attractive to build if Cold Ones were also available.
Overall, I think this is a superb mod! Especially with the proper map. It's still great on random, but it just doesn't have that Warhammer feel.
Plus there are some interesting situations on the Warhammer map. The Norse and Dark Elves have great opportunity for a sea-raiding strategy, The Old World is always a tight balance of shifting alliances and flash-wars.
The only thing that blows my mind is when the Empire or High Elves, etc, make alliances with Chaos!
Maybe it would be good to try a locked-alliance version with all good factions always at war with Chaos. Chaos would have to have some deadly stuff to make up for that, of course. Maybe a 1-per-turn unit-spawning wonder or something. Would make a fun scenario I reckon. I might bash one together on Conquests Editor to see if it can work.