I'm still very skeptical of the finances working out, but if they do get him I think it could be a brilliant move.
Mourinho's an underdog. Porto & Inter were his best work and Chelsea had a massive chip on their shoulder in 2003 as well. He makes his players believe they're fighting against the odds and it just doesn't work at clubs like United or Madrid.
If he's going to have another successful job, Spurs is set up perfectly for it. If anything is going to convince Alderweireld, Vertonghen, Eriksen to stay, it'll be the chance to train under one of the best managers of the last 20 years. There's a very good squad, CL group is pretty much done and dusted.
The timing is good as well. Spurs are 14th now, but only 3 points off 5th so he only needs a little bit of improvement to get them right up the table, and to be honest with Pochettino seemingly looking to leave at the end of the season, it might even be that firing him while Mourinho was on the market is a really, really smart move.
West Ham, Olympiakos, Bournemouth, United & Burnley is an easy first 5 games as well.
I think it's worth a go for Spurs. He could be the person who takes Pochettino's work and turns it into a trophy or two before the team breaks up in 3 years time any way.