Heroes 5.5 WarGame Edition - Tactical Edition.

Why would a hero gather troops if they travel with almost no army?

Well, I'm saying you could take them on the third week, for example.)

You can. And how do you show it in the game so the player doesn't forget?

I don't remember anymore, do you use scripts to change the troop growth rates? And is this displayed? If so, then it doesn't seem to be a problem.

The chain mechanic will not be supported (like in Heroes 4). Due to the high movement range, troops will be transferred quickly, but not instantly.

Hmm, that's worse... And will you be buffing the "call for reinforcements" ability to compensate? I mean, reducing the movement penalty.
In general, yes, it might not be very good without chains, I agree. Either set the values higher from the start (the troops from the castle are relevant anyway).