Ill answer some of your questions:
Is there any kind of "Ganking" to look foward to in Demigod?
There is to a degree
some ganking, but its definately not as common/easy to pull off as in DotA. On prison it is often possible to do this, as long as you stay out of the enemies reinforcements vision range, then its definately possible. Ive done it quite a few times before and have been ganked as well. But it definately plays a smaller part in Demigod than in DotA.
What kind of skills can be used together to create synergy between the Assasins or Generals?
Oh there are plently of skills. UB's foul graps with Rook's hammer slam is a nice example. You get the UB to hold your opponent while as Rook you initiate a Hammer Slam (this can also be done with other Demigods who have stuns). Also generals have moves like Shield, Bramble (gives your ally a shield that can absorb damage), life leech aura (your allies around you get life leech), penitence etc. etc. Not really sure if that counts as synergy between characters - does it?