Ive done the bridge + the mid flyer // both cambions and all the imps using a 4 character party with multiplayer tuned the way i wanted it to be tuned. There are skill cap ways to do things like using the Enviroment is a way to make alot of the content easier. When your playing a solo character your going to cheese as much as you humanly can to do content. Wizard and Eldritch Knight are the only characters ive seen do a solo run thus far. Which is essentially doing the fights the same way your exploiting magic missle and armor advantage and you still use things like barrels make fights favorable via positions where you can use shove from high ground, all of those things are tools your going to need to do to solo a run but the ship you should easily be able to clear that with any class / spec / build. I could honestly probably clear it with a character with all 8's for ability scores its not that difficult to clear the ship and as any race the ship is like a free clear unless your trying to clear zariel / the mind flyer. You can kill the first set of imps with like 1 attack so. Like wise you can clear the second set in a similar fashion using Oil from barrels and arrows dipped in fire.
When your at a numbers disadvantage tactics like that make sense. There are lots of ways to advantage fights. Like skeletons in the crypt. You can move them all while they are unconcious via str 16+ character 17 is easier. to one corner with the switch res them and aoe kill them with 2 attacks. You could also do something similar using barrels with a single character. Slow time, Haste pot, push button end turn cleave jump clear throw barrel with any flammable object placed. Thats the solo way to do the fight you can also prebarrel and use a fire arrow plus cleave with the right placement of the adds and the fire. Prebarrel pop oil fire press button cleave the adds when they spawn. They will all die from fire ticks on there turn if your cleave hits all the adds.
There are plenty of ways to go outside the box for advantage. I mean you those effects are thinking outside the box that as a dm players should be rewarded for being creative. I've played more than my share of campaigns where i got creative to shut the dm down on stuff they were like theres no way you guys will survive this. Skeletons around dismember the corpses before they become a problem. Necromancer is a problem strip the graveyard at night to remove any options to animate dead bodys for the necromancer. Large number of enemies buy poison with delayed effect deliver it with free wine. There are lots of ways to get creative to even out numbers in a fight when the odds are against you having ways to do that is not something I myself am against. But it should not always be something that feels like your doing the same thing frequently I think chapter one limits that a bit as a lot of the map situations make that the best tactic.
I would home they think of alternate ways to get around that down the road. Water soaked ground is a good way to stop fire issues. Make people get creative use lighting ect instead or ice + arrows to be different.
