Are Real Madrid an ageing squad? Anyway, The question you pose is difficult to answer as Bale was frozen out for the best part of a year or so, in which time the injuries have taken their toll on him. He isn't able to do those 40 yard sprints that often and he's lost half a yard, even without injuries he'd be slowing up a bit now.
The crucial bit is this (for me) Bale is able to adapt his game, he has the intelligence to know when and when not to go for a ball, is brilliant at putting himself in positions in the final third where he can create game winning opportunities for others, he has a quick mind and is a much better player than Hazard in every respect. I don't think that Hazard has the belief or winning mentality of Bale.
To answer your question, yes they are missing him, they're missing his intelligence in the final third, his ability not to panic, get drawn in and chase games. He was treated very poorly.