[@SgtEasy]
The orks are incredibly dangerous. However, the current orks are a mere fraction of their previous power. There were a group of orks that had maintained the power originally granted to them by the Great Old Ones, the Orks of Goro. These orks were so powerful a single Ork Boy was able to hold off a terminator. Their leader was a being of such immense physical and psionic might he was able to go toe to toe with the God Emperor, and broke the God Emperor's back. Their elite soldiers had the size and strength of PRIMARCHS. These orks were so much more powerful than standard orks, they're not even in the same league. And even then it's probable the original Orks were more powerful than even the Orks of Goro.

[@Savato]
Of course the villains will have OP shit. They always do. That's how stories work.

The point is that the villains won't work together. The tyranids are going to attack the Goa'uld, Outliners and Imperium in equal measure, and most likely they'll be responded to by a unification of both good and evil characters. Hell, even in 40k the tyranids are one of the few things that force everyone to work together. Even the Necron and the Blood Angels were forced to cooperate against the tyranid, and the Necron are literal soulless death machines. It's the reason the Tyranid exist.

The heroes, on the other hand, will unite. Nova is already starting to gather good guys, and is even trying to work with the Goa'uld. The art of cooperation is the greatest ability good guys have.