Sacrificing jungler for a support top lane is pretty fun
At least for me, enemy team suffers. Started trying this strategy after jungler on my team messed up and picked Braum as a support but we managed to stomp the game really hard harassing enemy top laner ridiculously early on and winning 2v2s with enemy jungler.
Having another support on a team in general is just so game changing, that much more utility becomes very noticeable very quickly. Ideally you wanna go for supports that can harass and kill like Bard, Karma, or Braum from my experience.
As you play top you gain ward control over the whole top side jungle and can roam mid for ganks easily. I find the strat works best with a play maker in mid lane as well. When enemy jungler comes to gank you should win the 2v2 if you have been zoning out properly. By mid-game once you get their top tower down (should happen really early) you can be a roaming support and ward everywhere.
Even if the enemy bot lane is ahead you should win 2v2 if they swap considering most top lane champions spike sooner.
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For the Bard game we were doing really well and I was making a lot of plays mid but our bot lane fed too hard early and I started racking up deaths later on by forced dives.
Of course tell your team before you try it. Also I feel that you really want a support that can dish out damage. I imagine that two tanky dudes being up will have a very hard time carrying unless you create a really substantial lead.
We don't play it like how a duo plays in Bottom Lane, but just capitalize on strong synergies/combos in order to have a really dominant lane phase that helps snowball into late game. Is it viable? I don't know. But it's cool to play something different when you can. Next we are thinking about trying Swain and champions with long and/or easy to hit roots.