They are interesting from the standpoint that they appeal to different miners. Each current algo attracts a different segment. ASIC, GPU, or CPU miners pick their algo based on efficiency or advantage. CryptoKnight in particular appeals to CPU miners because there is currently no GPU option that I'm aware of.
CryptoKnight and Keccak look interesting.
Any possibility of adding new algos in the near future?
Just for the sake of adding algos? What do any algos out there do that the current Myriad algos cannot?
It needs to be more than interesting to undergo the hardforking and accompanying complications required for this.