Personally, I think this is exactly the way to think of it, and honestly I think there's a really good team to be built around this idea, with a number of great fits already in house. I think people get caught up in the "they're only going to go 3 innings no matter what" idea, when in reality I believe things would certainly be more flexible than that. I think the other item to consider is that we don't necessarily have to fill the rotation with just bargain bin pitchers. There are plenty of pitchers out there with health concerns or innings limits that I think would be perfect for this type of setup.
If you're still with me at this point, let me just propose a scenario that fits this method, while also building what I think could be a strong potential playoff rotation.
The way I'm thinking something like this could work is essentially with a 3-tier pitching staff consisting of: starting pitchers(5), bulk relievers(4), traditional relievers(5). First, to fill some spots internally we will have: Ryan and Ober as two of our starting pitchers, Jax and Dobnak as two of our bulk relievers, and Rogers/Duffy/Thielbar/Alcala as four of our traditional relievers. That leaves us with 3 SP, 2 Bulk, and 1 Traditional spots to fill.
To fill the final reliever spot, I'm signing someone like McHugh or Knebal to function as a high leverage, proven arm. I want these 5 relievers to be lights-out arms that can shut down the 7th-9th innings.
To fill one of the bulk spots, I'm swinging in a trade to bring in a guy from Miami, Elieser Hernandez. There are countless guys both in the organization already and outside of it that I think could fit these roles well, so I wouldn't read too hard into the one specific player I picked. But I did just want to show one stat line quick about why I think someone like Hernandez would be great here:
1st Time through the order: 25.3% K-BB% / .675 OPS / 2.54 FIP
2nd Time through the order: 15.6% K-BB% / .828 OPS / 6.31 FIP
The last bulk spot could simply be a rotation of AAA guys as arms are needed throughout the year. I'll let you fill in the blank there, I'm not going to think too hard about it. Eventually I think these could be ideal places for Duran or Canterino to end up long-term if they end up showing they can't handle a starters workload.
Finally, I think there are a number of interesting non-bargain bin candidates to fill out the rotation. I'm looking to identify players who maybe have a long injury history and have never hit the 150+ inning mark but are extremely effective when healthy, players coming off of an injury looking to manage innings and slowly build throughout the year, or young players like Ryan/Ober still building their workload. Nobody says these guys have to be scrubs.
Two pitchers that I think would be perfect for this type of rotation are Alex Wood and Alex Cobb. Both have an extensive injury history, but have proven to be strong starters when healthy. Let them go out and get their ~15 outs, throw 75-85 bullets, and help to manage their workload throughout the year so they are healthy and fresh going into playoffs. Then to top the rotation off, I think a great fit for this setup could be Carlos Rodon, as someone who is coming off of an injury and maybe doesn't have the capacity to be counted on for 150+ innings. Maybe his market isn't quite what he was hoping it to be, so we swoop in and offer him a 1x$22M contract to let him rebuild his value. If he's healthy going into playoffs, there's a Game 1 starter you can feel real good about.
I'm not saying this is the most realistic offseason, and if you asked me if I thought this plan was likely to be put into place my answer would be "of course not". In reality are we going to sign Rodon AND Wood AND Cobb, no definitely not! And would 1-2 of the SP spots and 1-2 of the bulk spots be more likely to be filled with the Chris Archer's of the world, absolutely! But some people are writing this off without even giving it consideration, and I think that's a mistake. We would all love to sign the Gerrit Cole's and Scherzer's of the world, but that's never going to be our reality here. I think ideas like this can allow us to be competitive in a "Rays" sort of way, while also not constraining us to a $70M total payroll.
Full pitching staff for this specific scenario is included below for clarity's sake. There are a million variations of this that you could put together, but this is just something pulled together on short notice.