I didn't say you couldn't make it work - just that it's the "worst party composition" that I can think of. Adding almost any other class would make it better.
Which you did in your example by having one of the rogues multi-class into cleric.
"Adding almost any other class would make it better."
But that would apply yo almost any other "all one class" grouping. Same lack of versatility applies.
the point i was trying to make is that rogues **can** actually reduce your specific complaint "lack of healing" in quite a few ways and have ways to deal with the issue in-class with the stealth and damage outputs. they have built-in ways to avoid taking damage through surprise, avoidance and even just doing good damage output. healer feat plus sub-class gets you bonus action healing too.
With expertise available for all variants it should be easy for an organized and coordinated group of rogues to have a lot of bases covered well and ways to directly avoid or mitigate the need to heal tons of damage.
Not as true IMO for some other "single class" options but then, all classes have a fairly wide variety.
if i were to pick a single "one class group" for fewest types of solutions and reactions it would likely be five barbarians. their tricks are almost exclusively focused on either doing damage with weapons (melee mostly but not necessarily) and soaking damage. Thats not a lot of tools in their toolkits.
And like the five rogues, swapping one out for almost any class would help a lot.
As always, it comes down to challenge is two parts - "what you need to do" vs "what you are good at." Five barbies would solve a smaller set of challenges very very well but five rogues would solve a larger set of challenges - maybe not as flamboyantly. I
IMO.