Firstly, I want to say that I don't think he is biased, at least in a conscious way. For me, he is all about narrative in which he thinks is the best. Therefore, if there is any opportunity of an underdog win or a score that goes against the consensus, he rams that home.
Secondly, he also has the issue that he is 77 now. He simply is past his sell by date as anyone would be at that age (I don't say this in a bad way) as obviously age takes the edge off of everyone in terms of enthusiasm and energy. I mean, seriously, can anyone say that they improve with age outside of things such as knowledge and wisdom etc?
For me the bigger problem with him, is that him and Gray worked extremely well as a pair. Individually, I don't think they're great but as a pair they complimented each other very well as Tyler could do the narrative and Gray could do the enthusiasm; whilst their voice also balanced each other well for a British audience. For me, Tyler hasn't ever been able to rekindle the dynamic he had with Gray which is the primary issue, after those listed above.