This is one issue on which SE has pretty clearly said "No", again and again. The reason they usually give is that another page of inventory information would put additional strain on the servers every time a player logs on or changes zones. In my opinion, though, if we're already so close to critical strain so early in the game's life (FFXIV doesn't even have a single expansion under its belt!), I see grave problems arising in the not-too-distant future. If you consider main-hand weapons/tools alone, once the three Heavensward jobs are added that will be potentially 23 out of 25 slots used up if a player wants to be able to change to any class on the fly. Presumably there will be many new jobs added over the lifetime of the game, and we're already nearing the limit of what is possible without adding at the very least a second page for main-hand tools.

SE's going to need to put some serious thought into what to do about limited Armoury space - and as they do, I hope that they also take the time to reevaluate the possibility of a Tackle Box...