These changes would actually make for such a more engaging gameplay... Its quite a shame actually, with the new seal mechanics they found a nice solution against balance fishing, since other cards would have also been desireable. but they went one step further and instead of solving the problem, they ripped it out by the roots, destroying anything near it in the process. i know thats a bit overexaggerated but thats how i feel about it.

Back to your sugestion. It might be a tad to powerfull to give 3 buffs during a no different seal but then again, it would raise the skill ceiling and they could easily number tweak it.