No, don't do it.
If your heroes are fully equipped, Kellars Keep and the Witch Lord are a little bit easy. Then you can apply a rust spell here and a twist wood there so that they can keep spending their gold on something.
With beginner's equipment, it's not possible to play KK and ROTWL
The Ogre Horde and Morcar's Mage are a step up from there, you'll see some certain hero deaths even with full equipment; so if they don't know how to spend their money you can (strongly) hint that mercenaries are worth a try.
Elf Quest and Barbarian Quest are incredible difficult if you play them as written, so, full equipment it is again.
You can offer your heroes some potions beyond what they can buy in those heavily overpriced potion shops - give them a heroic brew for 45 gold or a potion of strength for 60.
You can offer them also some cheaper mercenaries, like a Pirate with AT 2, DE 2, move 10, 1 BP, 1 MP for 30 gold...
I made also some intermediate equipment that fits between the others and some equipment which is better than the base game, but incredible pricey.
Additional offer in the shop, additional rust spells... the game keeps being interesting.
KK, WL, Ogres, BQP and in parts also EQP play multiple quests in a row without shopping. That's awful because it takes away the treasure hunt aspect of Heroquest - what do you need 1000 gold for if you can't go shopping? So I would try and find a way to let them go shopping at least every two quests.
We tried something here for Kellars Keep; great thanks to mikemacdee.