I think it's fine to take aspects of FFXI and bring it into FFXIV. However, what some people are asking for is "Change the entire core of the game to be FFXI and keep some side aspects of FFXIV...and do it as quickly as possible". That's just not realistic.
For example, itemization structure, including things like Set Bonuses, different types of Materia, Secondary Stat restructuring, and the like are fine to discuss. However, don't expect anything like that in a patch. That's clearly expansion territory. The Devs are going to keep massive changes like that close to their chest until the Fanfest most likely. They don't want to promise massive restructuring changes right now, and then have them change completely in development. In fact, they've thus far been incredibly quiet on what content will be present in the expansion. They're saving all big reveals for the fanfest, which might be wise. They don't want to cause a panic if they can avoid it. Temper your expectations though. FFXIV will never be FFXI-2, nor should it be. FFXI, while not a bad game, would likely struggle in the modern market. The extremely slow pace to leveling and gearing up is something that most modern audiences don't enjoy. It catered almost exclusively to the hardcore, and in modern times that doesn't make for as successful of a game. MMOs need to entice casual, hardcore, and "midcore" (however you choose to define that) audiences, and that's why we see things like Diadem and Palace of the Dead cropping up. I have no doubt that 5.0 and the new expansion and it's patches will bring new content similar to it, and likely expand upon those as well. I have a feeling that the new expansion will shake things up a bit, though only time will tell. It's just foolish to expect a major shake-up before that point.
Change is a scary, scary thing for players, especially when it's with a game they love. People talk so passionately about games not because they hate them in their entirety, but because they enjoy the game and want it to be the best it can be. Unfortunately, there is never a single vision as to what is best for a game. Some players will prefer more complicated stats and abilities, since they get to tinker with them more. Others prefer to be more useful out of the box, and minimize their chance of being useless. Some prefer slow, methodical grinds, and for their hard-won equipment to give them a massive edge over everyone else. Others prefer less of a steep difference in equipment between casual and hardcore audiences, allowing them to play together more easily. Still others don't care about equipment much at all. Some prefer incredibly complex rotations, while others prefer it more simple. Some play primarily for the rewards/gear, while others simply enjoy the content or the challenge. There is no single right way to go, so for now SE is trying to appease as many players as it can. Sometimes that player is you, sometimes that player is someone else.
Basically, don't expect major changes immediately, but it's fine to discuss what you would enjoy. Don't expect confirmation on major changes either, just enjoy the discussion. I'd just prefer if the tone was more "here's how we can improve the game" and less purely negative. Think not only about what you dislike, but what you enjoy about the game. Everyone here clearly enjoys the game to some extent. Think about what you like most, and how that can be improved, rather than completely overhauling the entire game. If you like nothing well...I'm not sure the game will ever truly satisfy you.