Some thoughts after getting thru 2/3 of the game:

Titans, especially the lighter ones, and Superheavies rock
Tanks and lighter vehicles are next to useless, they cost a lot and die from just about anything
Heavy Weapons are preferred to infantry
is it me or does artillery somehow do a much better job when on overwatch (eg. waiting on my turn so they can shoot on enemy turn)
Artillery is a must, I had the best results with Whirlwinds, somehow Basilisks and Bombards seem to miss much of the time, though see above
Flyers are useless, almost every unit can kill them

I wonder if anyone has their own roster.

BTW is a hotseat multiplayer possible?

I did play hotseat MP back in the day.
As for titans and superheavy being better than regular vehicles, that is definitely true.

Superheavies can be one shot by a leva lacha, though, which can be quite a problem.
The missile launchers (deathstrikes) are also very strong. They can each shot only once, but they pack enough punch to badly damage a gargant, or vaporize most superheavies (with warp missiles).

The APC are still useful for storming the objective, though, but vehicles will die very quickly when in range from enemy infantry (especially the ones with more heavy weapons, I don't remember whether these were the Bad Moonz or DeathSkullz).

Heavy weapon infantry is definitely the way to go: twice the fire power, and increased range makes them much better than regular infantry (or Space Marines).

I checked the values, and compared to the TableTop(TT from now on) Space Marines/Titan Legions:
Infantry is weaker against armor, but is much more resilient, because you only kill one model at a time instead of the whole squad.
The cost of infantry is roughly on par with the TT.
The cost of artillery is 30% to 50% lower than in the TT
The cost of regular tanks (not superheavy) is 50% higher than in the TT
The cost of superheavy is 20 to 50% higher than in the TT, but they have 4 HP instead of one.
Titans cost the same as in the TT. They have much crappier weapons (you don't have to take a close combat weapon on a warlord, and you should almost never do so. You also don't need to take a missile, and most titan weapons fire several times a round), but they are much more resilient (you could endure several hits on the TT, but each one had a chance to hit the Titan reactor and destroy it).
So I am thinking about modding everything to bring it back in line with the TT.
It is even worse for orks, because they don't have good ways to deal with very heavy armor.