I didn't miss that part KG - Pace declines with age. Ability doesn't, nor does footballing intelligence. Walters only real attribute was his pace, which is long gone and he's played 3 times in the last year with a net contribution of no goals and one shot that was off target (and only 23 appearances the season before so not sure all 7 of those "Prem seasons" should actually be counted).
RE: Dublin - I'm not overly sentimental towards him. He was just a far better player than Walters. He had the football IQ to drop seamlessly from Striker to CB and do a pretty decent job there. Walters couldn't do that, he doesn't have enough about him. Imo (and it is only my opinion, you're welcome to yours!) you over-rate Walters - he's got 50 ROI caps, it's not like he's in the German or Brazilian team. Walters has always been a bit of a one trick pony - hoof it up to him and he will run in behind or win the flick on - he may still win some flick ons and cause us a few problems in that way, but he isn't getting in behind our defence.
With all due respect to ROI - Daryl Murphy who has 14 goals in the last two years and is 35 years old started their world cup playoff game (in which they got spanked 5-1 by Denmark at home). Gary Doherty got 34 call ups for ROI. International football is international football and you can't help the country you play for (well I suppose to a certain extent you can) - plenty of great players have played for lesser footballing nations but his competition for the national team place was Simon Cox and Andy Keogh. He was hardly beating out Messi to get in the side (although given the fact they couldn't get Hoolahan into the side due to his playing style, you do wonder if they'd have found a spot for Messi anyway). I'm not trying to diminish the fact he played at international level, but putting some context around it doesn't hurt. International caps has little relevance to ability.
There's no probably about it that Dion was a better player. Stats back it up. Goals aren't be all and end all as Walters played a wider role, but goals + assists, not to mention Dion played for Man United and Walters highest echelon was Stoke tell you all you need to know.
311 Prem apps, 111 goals, 40 assists
233 Prem apps, 43 goals, 19 assists.
Simply put - you can't really compare Dion and Walters - they have/had different skill sets, and Dion's had far more longevity than Walters' does in my opinion. Regardless of ability, in age terms it's not a relevant comparison due to the differences in their style. Walters relied on a diminishing asset in his pace, whereas Dion was just a more complete player.