I had an idea to make a deck format, but then I realized I cannot set the rule for that. The basic was to build a deck with cards lower or equal Power of 5(4 also came to my mind, but 5 looks fair enough). Most of the time cards with higher Power are preferred in play, so this is why I thought to make a format like this for an event or such. Sure a few cards like Copper or Marco Cr would be dangerous in it, but it would be fun to play. Only downside I see is that newer clans like Berserk, Frozn or Jungo barely has any cards for this format.
What do you think about this idea?
Sure you can. It's just incredibly tedious to do.
Eg, "You can only only use the following cards: Allison, Amelia, Ashley, Bhudd, ... Zlatar, C Beast, Galen, Negodz." There's only 246 of them, afterall.