Soft forks were a mistake; they allow Bitcoin to be corrupted without consensus.

Changes should always be hard forks.

Soft forks allow changes to be made whilst everything continues to function; this means that the vote of nodes that do not accept the change is meaningless, as everything works regardless.

In a soft fork, nodes that do not update retain their veto over the old rules, but lose their veto over the new rules.

So running old versions is pointless, as some people claim.

And finally, Bitcoin was better before SegWit.