That has more to do with the obscene range of some units in 40K than it has to do with anything else. Deployment interacting with who goes first has little to do with that.
It has a lot to do with deployment interaction. Where models are placed matter less when they can shoot across the field. Thus, the alternating deployment matters less because there isn't a great deal of tactical back and forth. This is evident by the change to deployment being a boon versus a detriment.
Placing all your junk in 1 move does the exact opposite of trying to convince your opponent of deploying badly though. I like the alternating deployement AoS has. And battalions deploying (potentially) at once is in this phase indeed something that can be interesting. However, who goes first has nothing to do with trying to hide information to gain a favorable position as it's just a matter of "I finished first". Even the potential for bluffing is increadibly limited as competitive lists don't have that much variation & gauging how many points the opponent has already put down shouldn't be too difficult either giving you a halfway decent chance of guessing what's not yet on the table anyway. And that's ignoring relativly common situations where you just get told their list before starting...
A battalion can be deployed in any number of drops at any alternation. If a 1 drop is being deployed correctly then you will only ever be one drop short of your opponent (unless they have massively more units in their list than yours). This is why I value low drop list. It allows you to gain the maximum amount of information and then decided who will take the first turn.
You should never have to guess how many drops your opponent has left. Both players should know exactly what is in their opponent's list and how many drops they will take to deploy.
I am not following your argumentation at all. Perhaps I have misunderstood your grievance with the set-up phase.
Deployement itself I'm fine with. It's just the whole "who goes first" bit that I dislike. And that bit I'd argue takes away from the tactical depth as it encourages you to dump as much as possible on the table at once.
This has never been my experience. Most of the tournaments I win are because of deployment. Deployment, movement, and foresight are what allow a player to score more objectives. Having control over the initial turn sequence is tactically valuable. A price can be paid to have a greater chance at gaining this advantage if you value it. Seems like a perfect system to me.
The "cost" of a battalion should be that you're forced into fielding a certain force composition which limits your options, certain tax-units that don't necesarly pull their weight, & limiting the synergy between battalions both by having overlapping units (of which you don't necesarly want multiple) or by having 2 battalions with wildly different focus that won't necesarly work well together.
This is currently the case for many super battalions. To field your average supper battalion you will be playing 300-500 MPP in models down. That is a big ask.
As for max units; there's horde bonusses, buffs affecting an as large as possible unit, max unit cost & the potential of tarpitting. Units that don't really benefit from any of those already don't have much of a reason of building a maximum unit anyway so that wouldn't change much imho.
In my experience this is not why people take MaxSU at the tournaments I have been too. There are plenty of maxed units that do see play often and have no unit size bonus, or are stacked well beyond the necessary mark for the unit buff. Big units hold objectives better than smaller ones and require less drops. That is why they are valuable.
My, how threads go off topic. Perhaps I will make a tread about the merits of battalions in the near future.