Oh yeah, I agree Milotic is definitely better than Whishcash outside of availability. Availability is by far the biggest reason (though its Ground-typing also matters).
Tentacruel does have better stats (notably higher SpDef and Speed, slightly better SpAtk), but I think its Poison typing...
Barboach can be obtained at Route 208 (left of where you get the Good Rod). Also, I do believe its stats are good enough. Sure, they're not impressive, but they're similar to Lantern and Dewgong, both of which are effective mons due to their typing and access to strong moves such as Surf and...
I also have some points for DP Pokemon that should be reconsidered. This is not a complete analysis, however:
Again, this is all just for consideration. This is mostly to give credit to some forgotten mons (mostly Barboach and Remoraid).
Just found this thread. I have some arguments for Snover:
Snover E--->B (maybe C) (DP)
I'm actually surprised to see Snover that far down. I used it in my Pearl run years ago, and I think it's one of the best late-game Pokemon (and probably the best non-Legendary one)! I'd love to give it...
LF: 31/0/31/31/31/0 Male w/ Relaxed/Sassy/Quiet nature. Any pokemon that can breed works.
31/0/31/31/31/0 Female w/ Relaxed/Sassy/Quiet nature in the Water 1 and/or Dragon egg groups.
Trades in description
I understand. PM would be best, since I'll know once I see my phone (emails). It may be difficult, however, due to differences in time zones, but hopefully we find a time when both of us are free to trade.