It is a bit of a misleading question as you have assumed I believe everything is already homogenised and therefore interesting. I do not. The problem I see with many people's viewpoints is that they look at things too broadly, and don't look at the nuances that makes things different. To use an extreme example, all jobs use the GCD and oGCD to perform actions, therefore everything is homogenised. Obviously, that is an absurd claim to make, but it is technically true. What we have to do is look at the individual skills and see how they differ, and this is where things tend to split between many people's view and mine. To give a clear example, if you had 2 GCDs, both do 100 potency of damage, but one had a cast time. They are obviously different, but there would be some that claim, well, the result is the same, therefore they are homogenised., whilst ignoring the fact one of them has a cast time.
To give an example of this, before DT, but after we had the media tour info, someone was claiming that Ninja and Monk played the same. I provided quite a long post explaining how the jobs are different, between how the jobs burst, their filler etc. were different. The response was, yes, but they both have a 60 second and a 2 minute buff, therefore, they feel the same. Now, again, this can be seen as an extreme view, but it is something someone said.
Another one that comes up is Scholar's Sacred Soil and Sage's Kerachole. Functionally, they are the same, but they are different in how the resources needed to use them are generated differently and the benefit to the SCH/SGE are different, plus, they radiate from different places (SCH is ground target whilst SGE is from self).
I can keep going with things that seem the same, but are different, but that isn't the main point here. In my eyes, things ARE different, the problem is, those differences do not necessarily shine through and this is down to things that have happened. To provide an example, using the above from SCH/SGE again, when they massively increased the radius of all these effects, it stopped mattering whether it was a ground target or from self, as the range is so big, it doesn't matter. It isn't that they have directly made them the same, they have just made that difference not matter.
We can also talk about what does it actually mean to be different? If Kerachole was a shield rather than a % mitigation, would that make it more unique? You would use it in the same places, nothing has changed there, but would it then stop being classed as the same as Sacred Soil?
Which brings me onto the next point. What would it actually take to make things not homogenous? A tank needs to be able to mitigate damage effectively, regardless of whether it is physical or magical (if you make them useless against one or the other, it prevents them from being taken into fights where that damage type is most used). Remember, every tank has to be able to clear every piece of content, so they need to be able to mitigate both sides well enough. What does this then leave you with? % mitigation and shield mitigation. There is only so many ways you can mix and match those concepts before things start to look 'samey', so how are we changing things to make then unique to the tanks? We have had suggestions of Parry/Block/%Evasion, but those are all just different names for a straight up % mitigation, with downsides.
Now, to prevent any misunderstanding, I do not think the system is perfect. As is a common theme, the 2 minute meta has destroyed a dimension of avenues that jobs can go down, the main one being damage profiles. With the 2 minute meta, every job is a burst job, even tanks and healers. It has necessarily killed off any sort of sustain jobs. My fix for this would be quite extreme, but zero temporary raid buffs. The damage stacking from raid buffs is what has ultimately caused this meta to form, so getting rid of it completely will change this dynamic. I do understand that some people like to be able to buff jobs and help others out, the caveat is that any damage buff has to be able to be upkept for the whole fight and not have periods where you can increase it higher temporarily. The other type I would look at is Brotherhood and Arcane Circle. Taking Brotherhood for a second, removing the damage component means the only thing is the Chakra gain for Monk. As long as your team mates are attacking, you benefit the Monk and help them out, but it also doesn't matter where in the rotation the party members are. Bursting or not, it doesn't affect anything. Similar concept with Arcane Circle and Plentiful Harvest.
Now that raid buffs are either permanent or do not affect the damage of anyone else but the user, we can look at rotations. There is no 2 minute meta to follow, you are free to use whatever timings you want. You can also give more agency as to WHEN you burst, if you have that capability. As an example, Viper. The only reason it used Reawakening every 2 minutes is because of the raid buff window. Get rid of that and you get more freedom as to when you use Reawaken. Now is not a good time, so I will save it for a bit, or, I will use it earlier to help push the phase or kill an add. This doesn't necessarily mean you cannot have a stricter job that is much more rotation focused like Dragoon, they are just different ways jobs can be different.
There is a lot more that goes into this, but I do not agree with the blanket statement that all jobs are homogenised.