Well I would argue the fact that Walker was our undisputed first choice ahead of Trippier before he asked to leave, was in the PFA team of the year two years in a row, is the second most expensive defender of all time and just recently won the Premier League whilst once again making the team of the year is quite substantial evidence myself....
And in the 18 months of Trippier playing first team football, he has surpassed Walker in most apsects of the game other than being really fast
I would argue Walkers pace and athleticism is very much a talent!
Its nothing you have to learn or practice though.....those areas he is weaker in
I assume you have seen Trippier trying to defend against wide players like Martial, Sane etc? If you genuinely think Walker would have struggled in the same way he did then I give up...
Ive also seen him against Ronaldo and Marcello, and Salah and Mane and Hazard and Willian....he did just fine....just like he did when we beat Utd 2-0 last season and they didnt get a look in.
Have you seen Walker against Salah and Mane by the way?