Early on in our exploration of these tanky damage guys (before we had any naming convention for them or anything like that), we actually did group Singed alongside the guys being updated in 5.16 and a few others as candidates for updates, and I actually did a few tests worth of exploration on Singed specifically to see how he might fit in with them.
What we decided/learned was that, although Singed is indeed a tanky melee guy, several characteristics of Singed made him much different than the others, and so he probably didn't belong in the same grouping despite the similarities. The main reasons I remember were:
- Singed as a character seems to be all about wanting to be slippery and unstoppable, and Juggernauts are intended to be more controllable on average than he can tolerate being.
- The coolest version of Singed probably plays up or re-imagines cool uses of his more tank/cc-like spells, Mega Adhesive and Fling (Poison Trail is already pretty cool/unique as is).
At the end of the day, Singed will have Juggernaut elements to him, but we didn't want to explicitly push him harder in that direction given the fact that he's already a pretty cool and unique character, and much of all this Juggernaut stuff was about making characters more unique within the groups they share many similarities with.