The way bandages currently work disincentives using higher tier bandages. Due to the healing effect being cancelled upon hit, players are more likely to not want to "waste" bandages because they get hit. The players who can block/dodge the hits to get the full effect of the bandage are not likely to get hit as much. 

So higher tier bandages should be able to take a hit or two before "breaking." This will incentivise using the higher bandage tiers despite the cost, even if they don't get more healing. Then players who get better are rewarded by being able to use cheaper bandages.

Your idea is fantastic! I love it! I hope the official team sees it! However, the bandages in the first game were a bit too simple and overpowered. I think your point about "being able to withstand 1-2 attacks without interruption" is brilliant. It allows players to better judge when to use bandages, increasing the fun and strategic thinking in the game, instead of using them haphazardly like in the first game or being afraid of wasting them in the second!

It suddenly occurred to me, maybe I got it backwards? Higher-level bandages should be designed to heal more, but their healing will be interrupted immediately upon taking damage. Conversely, regular bandages heal less, but can withstand 1-2 attacks without interruption, making them more suitable for players who are not good at perfect parrying. High-level bandages are high-risk, high-reward, and are the choice for players who rely on perfect parrying.

Eh, with how easy it is to craft smoothies in bulk, I think bandages deserve a different function.

My preference would be that bandages heal a set amount of health spread over a number of ticks, like 70hp in 10 ticks of 2-3 second intervals. Getting hit during the effect would simply pause the healing for the duration of 1 tick, but if you avoid being hit for long enough it keeps going again. I'd also make it so the healing effect is paused when you're at full health, and I'd give bandages 3-4X longer duration (but the same number of ticks). This means that they don't waste healing when you're at full health, and the healing resumes if you take a bit of damage (but the bandage still wears off over time regardless). That also means if you're getting hit all the time, the healing won't ever kick in, but in that situation you should probably be chugging smoothies for health recovery anyway.

This way, bandages would serve better as post-combat healing, since using a smoothie to heal after combat ends means you're probably wasting the buff effect it has.