It wasn't a sacking, Holloway said he didn't feel like he could continue and hence, mutual consent...
He admitted mistakes in the Press Conference, which takes quite a brave man to do in the field, and as such I wish him all the best... Regardless of whatever happened over the past year, we still have the Play-Offs and that win at Brighton to remember...
I would rather if he didn't feel up to it (and tbh, after Fulham, previous matches with dodgy incidents and the reaction of some 'fans' on Monday, I don't blame him), that he would do this, rather than stick around and things get worse and worse week in week out...
As for a replacement, the sensible option with an aim to stay up would have to be Pulis, because of how his teams are... It wouldn't be pretty but it would certainly help the major issues with the team which is both 1) defensively dire and 2) often too honest for their own good... I would happily see us play 'ugly' football (which would certainly be better than Monday, or Palace under Freedman or Taylor or many others) and stay up than more Monday performances and go down with an award winning low points tally...
Give him a 2.5 year contract to acheive some form of stability to both the team and club (regardless of league) and see how it goes from there... As Holloway said, the team need a new injection of something into them, as it appears that his mistakes may have cost him the back-room confidence of the players both old and new...