Like having a bodyguard group with mixed heavy infantry. If I wanted that before, with say Legionaries, I would need to assign ALL legionaries to group say 6, and not just around 10% that I can now with the new system.
The new system is superior to the old. Anyone saying elsewise just does not understand the system or have experienced bugs with it.
Remember, just because a lot of voices on the forum complain about one thing, does not mean that complaint is justified. There are tons of people out there playing the game just fine with the new system.
You could do that with the old system. Assign the bodyguards to 1 group and then split them in battle. What you are saying is simply is not correct.
Neither system was perfect, but the new system is a huge step backwards. I cannot for example split units of the same class by tier. That's a huge problem when I'm trying to level up certain units.
Also, if a system is so prone to bugs, it's clearly not a step in the right direction, because it is inherently bug prone, or should not have been deployed until the bugs were fully resolved.
As far as the last comment, I'll say what I've said in the past. Someone that isn't posting isn't necessarily agreeing with you. All it means is that they haven't posted, not taken a side.