If your deck completely falls apart because you do not have access to your commander you made a bad deck, plain and simple. You can certainly build a deck that's primary strategy involves your commander, in fact I much prefer decks that do (or at the very least benefit greatly from their commander), but you should always have a contingency plan. Removing the tuck rule simply encouraged bad deck building by removing a check for decks that were overly reliant on a single card they always have access to.
I understand you argument, but that is a very spikey perspective. What about the Jhonnies and Timmies? Commander allows me to build decks around mechanics unique to specific legendary creatures, decks that could never funcion in a format where i don't have guaranteed avaiability of a certain card. Brudiclad, Telchor Engineer is a prime example of this. Would that deck work once the commander is tucked? Definately not. But why should that make it a bad deck? It plays well (in the absence of tuck), its fun, its unique and it has cool flavor. Now YOU may not care about any of these things, but a lot of people do, and in my perspective that makes it a pretty good deck. Maybe putting together a deck that is filled with options to wiggle out of every corner is super fun to you, but thats not true for everyone. I don't want to fill half my deck with tutors and counters, both of which make commander games unfun (for me) in large numbers. Point is, preventing tuck opens up a lot of interesting deck builds and that is a good thing imo. My Commander playgroup nearly died because tuck was so frustrating and it flourished since the tuck change.
We'll take your Brudiclad example. So it is a red/blue token deck, while yes the ability to have your tokens become copies of another is really cool, is it really nonfunctional without that? You can't still just swing with a token army or make use of them in some other form?
That's where it goes into "poorly built", if you answer no to that.
so here's where i take issue with the whole thing. it really doesn't have to do with bad build or good build because a few different factors unique to edh.
we can all come up with examples of decks that will be crippled by a commander getting tucked, and examples where the deck runs just fine. let's say i'm playing feldon, i know if he gets tucked because of the colors i'm in (monored), i will never see that commander again this game. my options were run subpar tutors because of my colors, or just never see him. the subpar cards don't do anything outside of a tuck situation, or you can run things that just hone the deck better in their place. the deck can function just fine without him, but with him locked out like that you're removing half of what the build does, half that deck's purpose - there are tons of commanders that are built around like that and are further limited by color - its not really fair to remove half of a deck's capabilities so easily.
by the same token, if i'm running let's say a zegana build, and she gets tucked, well given what the build does, and the colors its in, i'll either tutor her up efficiently, or just draw into her within a turn or two if the deck is working. we can all come up with builds and commanders where this is true. so now accessibility to certain cards not only improves what the deck inherently does, but also gives it an advantage in a tuck situation. there's no downside for these colors/builds.
additionally, there's the problem of resources. you tuck someone's commander, now they have to spend time and resources to get that commander back. that sets them behind. that gives you an even bigger advantage over decks that need their commander to function. it becomes even riskier to play those commanders at all because they just won't be able to keep up. what you're doing is reducing the commander card pool even further without realizing it. when players feel certain commanders just won't ever be able to keep up in the face of that - they just don't build them. this was a phenomenon i definitely observed when tucking was a thing. the array of decks showing up weekly exploded just after the tuck rule changed because suddenly there was a fighting chance.
so the point i'm making here is that you can't really blame it on poor deck building every time. there are major limitations to some colors, and some commanders are just not going to be as competitive as others. on top of that, some commanders really want the deck built around them and that's going to change the nature of the entire deck reducing ability to deal with a tuck potentially even further.
now here's where it all differs from cranking the tax up. with the tax, you need multiple ways to remove the commander to keep cranking that tax up. on top of that, i can still produce mana. there are points where i can recast my commander, or maybe i go infinite and it doesn't matter anyway. the point is the options are still there, they're never really completely eliminated through a tax increase. i'm sure we've all seen games where the commander tax for someone is 10+ and they still manage to win by sticking their commander back in play.
all of this means, and i feel this is really important to consider in all things edh, that if someone sits down at a table and has half their deck neutered consistently chances are they just aren't going to come back. that's not a fun experience, and there are minimal ways to get around it if you want to play certain commanders. personally i feel that at the end of the day the format is a social one. anything that increases breadth of deck building and helps bring players back every week is more important than the competitive edge.
i've found the format much more enjoyable without tucking.
there's less shuffling, decks that are reliant on their commander aren't totally hosed, and generally things just flow better.
someone used the example of song of the dryads, but you can pop song, and your'e likely to have a way to do that through good deck building, you're less likely to be able to pull your commander back out of the deck, especially at casual tables or in certain colors.