I'm on the side that respec-ing has basically become an industry standard, and almost a must-have feature in a modern RPG (especially ones with complicated character systems).
Despite its potential to ruin immersion, it's just too big of a "campaign saving" tool not to include. RPG games are a huge time commitment. There are so many people new to 5E D&D - the system and the classes - and there are going to be many people who make mistakes in their builds, or choose a class thinking it sounds amazing and regretting it when it comes to play.
There's a reason why even Kingmaker eventually added this feature in. It's almost an expected feature in an RPG at this day and age.
