A SPAC is effectively (and I'm simplifying here for brevity) like a Private Equity fund. However, those are limited to accredited investors, and the general public can't buy into them.
SPACs could (should?) be limited in the same form. By prohibiting them from listing, it's the smallest regulatory change that solves the issue of unknowing investors buying something speculative without knowing it's true risks.
How exactly do you intend to do that? Remember the law is like code, not something you can rearrange on a whim.
There's no legal distinction of a SPAC. It's just a company like any other listing on the public markets. The better solution is to increase reporting and listing requirements for the companies they're merging with. The merger process should become exactly as it is with traditional IPOs; S-1 filings, roadshows, lockup periods, etc.
It's easy to do.
And you've killed SPAC as a concept.
To me this is one of the key differences between sophisticated and unsophisticated investors, and knowing how to do due diligence is really key.
OK - but how are you going to discriminate between SPACs and other c-corps? I don't think a porn style "I know it when I see it" test is going to work here.
But like another poster observed, not letting a SPAC list completely obviates the sole purpose of a SPAC (which I personally think would be an excellent outcome).
[0] - https://www.sec.gov/corpfin/disclosure-special-purpose-acqui...