Pretty much my thoughts too. I also can't get past the 27 players bought on his watch with the vast majority proving lemons - but I really don't want to get in a debate about this again.
I don't think you can make a statement about a vast majority of 27 signings being lemons without there being a debate about it really....
Here are each years transfers under Poch (I could only find 26 signings, not sure who I have missed?):
Year 1: Davies, Vorm, Dier, Yedlin, Fazio, Stambouli, Dele,
Year 2: Wimmer, Trippier, Alderweireld, N'Jie, Son
Year 3: Wanyama, Janssen, N'Koudou, Sissoko,
Year 4: Sanchez, Aurier, Gazzaniga, Foyth, Llorente, Moura
Year 5: Nobody
Year 6: N'Dombele, Lo Celso, Sessegnon, Clarke
Looking at that I don't think his record was bad at all really.
Davies, Dier, Dele, Trippier, Alderweireld, Son, Wanyama, Sissoko, Sanchez, Llorente, Moura, Lo Celso and even Ndombele (while Poch was still here) all decent players, some of them excellent.
Of the rest:
Aurier - is a decent attacking right back, better than many give credit for. He's not as good as Walker of course, but that's why Walker was a £50 million player.
Sessegnon - I think he has everything needed to be a very good player and has already shown that in patches at Spurs. I think he'll prove well with his £25 million.
Wimmer - did a reasonable job as backup for a couple of years and we then made a pretty big profit on him.
Yedlin - bought as a young punt, we made profit on him and he is now proving a decent player at Saudi Sportswashing Machine.
Vorm and Gazzaniga - are fine as back up keepers go (many PL teams have worse than those two)
Foyth - quite a few of our fans seem to like him. I don't think he is a bad player, just one who hasn't really found a position yet. I expect he'll still have a decent career in football at centre half for a decent European team.
Clarke - I don't think it is fair to class him as a 'bad' signing as surely it's still way too early to tell. There were also stories that Pochettino didn't want him at all hence the immediate loan to Leeds.
That leaves as true bad signings:
Fazio (I remember Poch actually wanting Hector Moreno but the chairman couldn't do a deal for him with Espanyol)
Stambouli (I think it was Schneiderlin that Poch actually wanted). We also still made a profit on Stambouli when selling him to PSG.
N'Jie
Janssen
N'Koudou (Pochettino actually wanted Mane)
Irrespective of whether or not Poch did or didn't want those 'bad' players above they actually only lost us about £20 million in total. A drop in the ocean really in the wider scheme of things.
That actually isn't a majority of lemons at all, even if you shift some of those in the 'Of the rest' list down a notch in to the 'bad signings' group.