Oh, you’ve asked so here is my view....
First of all without a doubt Aguero is a legend (I've written the following which gives my views on the use of ‘legend’ too. It's free for anyone to read:
https://gjfootballarchive.com/2021/03/30/aguerooooooooooooooo/ ) and we’ve been blessed with many others in recent years BUT we have also got a whole back catalogue of true legends (and I don’t mean cult heroes - that’s something else - I mean true giants of the game, not only for us but when compared to their peers).
If I had my way I’d have a whole series of statues lined up on either side of the road that leads to the main entrance. Top of my head would be Kompany, Silva, Aguero of course but also Meredith, Swift, Trautmann, Bell, Lee, Summerbee, Oakes... I’m sure others would be suggested and deserving but these were colossal figures in our history for various reasons. Then there are managers.
Beyond that I’d develop a Hollywood style series of paving stones/squares around the stadium listing all the other players people often think of as legends, I.e. cult heroes, record breakers, major goal scorers, players featuring in iconic moments. I don’t need to list them here because the beauty of doing Hollywood style stars is that you can feature almost every figure over time and turn each unveiling into an event.
A lot of people have talked about naming stands after players and, to be honest, this is something I’m against. I’ve always felt that you limit yourself by naming stands to four major legends. Had we done that in the past we may we’ll have stands named after Meredith, Cowan, Brook and Johnson - no disrespect to those players but what do you do when you then get a bigger legend? It becomes a minefield and some clubs have demolished or renamed stands named after legends.
The best way to remember a club’s past and allow space for future heroes is to build statues, mosaics, Hollywood style stars etc.