I think the 5 khuli loaches is quite a bit. If you are keeping them for snail patrol then 3 is probably enough. I am a fan of cardinals so I would skip the angle and keep the stock the way you have it only with 3 loaches.
If you have over 1w/g I would go with some crypts, vals, hornwort/cabomba, some hygros, anubias, java fern/moss, and possibly some dwarf sags. Get some branchy driftwood and attach moss to it for the cardinals to swim around. The effect is amazing. Check out Bk828's thread on his 55gal. for a model.
Good luck.