The runbacks don't bother me too much so far. I do think there's some skills in the runback, but it relies heavily on the level designer as well. An ideal runback:

• is relatively short, you should have time to reflect on the boss, but not get sidetracked
• has enemies that drop currency, so repeated runs slowly build you up (assuming you always collect your shade)
• has enemies that train you on the bosses timings or counters (if the boss is parry heavy, put a tricky-to-parry enemy enroute back)
• has a "speed route" that let's you bypass most or all of the run once you've figured it out

These factors make a run both interesting game play and still a form of progression. A badly designed run lacks these factors, being just a slow slog to get back into the boss fight.

My biggest complaint so far is the double damage. Every boss and so many common enemies do nothing but double damage. Why even have 5 HP instead of 3? And it being 5 (and bind healing 3) have compounding effects with this problem. Taking a single hit on the way to a boss actually costs you an entire "boss hit" so runbacks are worse all around. Trying to heal mid boss only gets you "one and a half" hits back which takes a lot of silk to build up and probably is a worse deal for you than just using the silk to power more attacks.

Double damage would suck a lot less (and be a better mechanic) if you had 6 HP to start, or if you healed 4 at a time, or if bosses didnt always do 2 damage. There's no tension to avoiding punishing hits because every move is equally punishing. It makes fights feel very conservative which is maybe intentionally meant to evoke Hornet as a careful hunter, using traps and plans to take down big foes.

I find the opposite though, she feels fragile and reactive. I wish starting damage was higher too. I had this issue in Hollow Knight as well, everything takes too many hits. Common enemies are spongy, bosses take at least 33% too long across the board. Especially it gets annoying since a lot of bosses so far get spammier and faster towards their final phases, so you spend so much time dodging the same attacks and looking for openings to chip hits in. Skills and traps don't do enough damage to feel especially useful either.

I also hate, and this is another compounding factor, the complete lack of enemy HP bars. On regular enemies this is annoying (gotta count my hits) but on bosses it feels negligent. Bosses have multiple phases and take so long to kill, it would be nice to know if my last run was just a hit or 2 away from the end or if I still had a 3rd phase to plan for. It adds to the poor perception of skills and traps as well. Sting Shard and Thread Storm both seem to hit several times, around a half-dozen, but neither seems to do much more damage than a couple of regular hits.

Overall I'm really loving Silksong, the art and music are top notch. The DLC for HK convinced me that Team Cherry and I disagree about some fundamental ideas in game design, and HKSS bears that out.