What separates Alonso from Amorim and the rest is that at Leverkusen he has managed to instill an incredible winning mentality. Their record this season is truly remarkable. The kind of run you need to be able to compete with Ped's cheats.
Sporting are currently on 2.6 ppg, with two narrow defeats and two draws all season, having lost their best players quite often, though that's perhaps balanced out by them having quite a big loan pool. He also won them their first league title in 20 years and has then on course for their second. Leverkusen on 2.69 ppg with four draws.
The two situations are remarkably similar actually, stats wise anyway. Sporting were probably the more consistent team of the two over the past decade but both were quite big teams in their league, both tend to sell their best players and not spend a lot, and both are now competing for league titles. Alonso looks like he might achieve the highest peak of the two, but Amorim has shown over five seasons that his title wasn't just a one off.
You could maybe criticise Amorim's performances in Europe, but then Leverkusen very nearly got knocked out by 10 man Qarabag.
The quality of the Portuguese league is often called into question but then we've also seen players like Werner, Havertz and Sancho come to England and struggle, while Kane has gone over there at the age of 30 and racked up the goals.