Ok, ignoring the 6e thing.
The only thing that has been lost is the players trying to game the system by choosing the "best" animal (or whatever being summoned). So, now, your summoned animal is a single statblock that prevent cheese weasel power monkeys from using the Monster Manual as a shopping list to eke out every single bonus they can.
IOW, you absolutely can summon a "seal" or whatever animal you like to summon. What you cannot do is abuse the system, just like every other caster, and try to gain advantages over the game.
Fantastic.