Blackpool have done very well despite losing one of their best players.
I disagree that you need massive change.
You need very good management and 4 to 5 quality additions.
Didn't Taylor just play for Bristol City in the Championship? He played 67 games in 3 seasons. I wouldn't bet against him scoring g in the Championship in the right team.
It's a little hard to predict though, isn't it.
I mean Peterborough & Blackpool both appear to have used the same strategy. As you said, 4-5 new additions to complement the core of the squad that got them promoted.
But although Posh were a much better side than Blackpool last year, they've really struggled and look set for an ignominious relegation.
The players that got them up (Pym, Kent, Beevers, Szmodics, Clarke-Harris etc.) have really mostly failed to make the step up to the next level.
Same the year before - Coventry did great; Wycombe struggled.
And the year before that - Luton did great; Charlton struggled
(I'm ignoring the perennial Barnsley/Rotherham yo-yoing because those two clubs basically permanently seem to play in the 2.5th tier)
Which I guess means it all comes down to the highlighted part of your post - can the management hack it, and understand how to set the team up for success in a better league against higher quality opponents?