Please bear with me; I'm trying not to repeat past mistakes, but if I was good at avoiding them, I wouldn't have made them in the first place. XP
Well that certainly isn't consistent then.
Fair point. We never received a Kabuto with the "Prehistoric Call" Ability found on Archen (PLB), Tirtouga (PLB), and Lileep (PLB). Do we have any other effect that can reliably bottom-deck it that is
not a Supporter (since the idea is to use Wally that turn) or a turn-ending effect (also a deal breaker)?
The rest of this does not mean I think a reliable T2 Kabutops build would exist if Wally were legal. Just wanted to be clear on that.
Also i don't know if supporter lock would be that bad. Part of the problem with item lock is that most if not all decks are over half items so most of the deck became useless and was easy to have completely bricks for hands. Supporters conversely are usually less then 10 and not only that but decks will most likely have to move away from relying on supporters because of the rules change anyway (to avoid just flat out losing if they have to go first) so should be capable of handling supporter lock (especially one that fails to set up randomly)
I'm pretty sure it would a reliable T2 Supporter lock would only be marginally better than T1 Item-lock. The Expanded Format
might be less reliant of Supporters than Standard Format, but not by as much as the reduced Supporter counts suggest. The Expanded Format contains Versus Seeker, and most decks are maxing it out; clearly, this is one of the big tricks that lets them run fewer Supporters. Decks use a lot of Items because they
need a lot of Items, and without that early game draw or search Supporter to keep your deck flowing, it won't matter that you are
not Item-locked; you'll run out of Items (or other needed cards) quite quickly.
Another aspect off this is the increased amount of potent Supporter-like Abilities. They can be used to get by without a Supporter, but they are also often used to ensure you hit a Supporter (or VS Seeker), because most decks can't go long without a Supporter. Either way, anti-Ability effects are pretty common plays, and two of them (Silent Lab and Power Plant) can be used
with Kabutops. In fact, if a T2 Kabutops deck was possible, I'm not sure it would be that much more difficult for it to also get one of those two Stadiums to the field. Even if you can't... a lot of those effects are one-and-done like Dedenne-GX and Shaymin-EX (ROS), so you're still facing the same problem of your deck bricking just a tad later instead of sooner.
As for how decks might change... it is possible they'll adapt to the new rules by
not really changing much at all. Strange as it sounds, if the current approach is sufficiently efficient, adjusting your deck to avoid losses due to the lack of T1 Supporter may cause you to win
less than if you just staying the course and eating the losses caused by the rule change.