I love the tenor voice above all others, and am very fond of Rossini - but it is very, very seldom that Rossini is sung better than adequately by tenors.
Indeed I know of only one tenor - Luigi Alva - who has sung the Rossini tenor roles as they should be sung.
Mostly Rossini is sung by tenors with far too heavy a voice - of the examples below Gedda was a Spinto tenor, which is of the same type as Pavarotti. Although he skillfully held-back on his full tone and volume, and lightened it - he cannot get anywhere near singing the decorations of the aria.
Florez is a lighter and much more flexible modern lyric tenor - but still too heavy a voice for Rossini - because although he manages most of the decorations, he cannot separate the notes, and this shows up especially in the runs (the scales).
Listening to Alva after these is a revelation: that is how it should be done. The notes in the fast decorations are separated.
Alva was not perfect - there is sometimes a audible aspiration between the separated notes - but he is the only one capable of singing Rossini in the style it should be sung - in which the decorations contribute a great deal of the value of the music. Without hearing these decorations given full value, the music does not reveal its full value.
Nicolai Gedda - adequate:
Juan Diego Florez - good:
Luigi Alva: how it should be done