I can understand the concern… I have used many s1 3-70’s in the second soul exchange for Lady of the Lake and I don’t miss a single one of those heroes, but love using Lady of the Lake. A regret on these would come if a costume comes along, given I only have 3 costumes for 5*… that isn’t very likely. HA10 is yielded zero costumes for me which is where what I blame my deficit on. Maxing a 5* takes about a week if I dedicate resources too it, so I am mostly out the mats on a s1 being used.
I am at 48 maxed 5s, you can’t use more than 30 heroes in a war and I have enough strong 4* to work for other depth related events like elemental quests and W3K so… getting rid of something unused for something used… isn’t too crazy.