Usage of 2048 bit RSA keys for minting alone would add 50-150 MB to blockchain yearly. Rest of transactions- well, they are paid(coinstake txs also pay fee but have 0.01 discount) so I don’t see a problem here.
Advantages: faster signature verification, smartcards, protocols/schemes.
It may be seen as a step backward in technology, in my opinion it’d give more freedom for the users, for which they’ll pay.
What’s your opinion on supporting RSA keys by Peercoin?