Ok, let me start with: I really like 5ed. But the homogenization of the casting and non casting classes is entirely our fault.
Let me explain. In older edition Pre 4th. You had to meet minimum requirement stats, alignement, race to do some classes. No elven paladin, no half orc ranger, no elf monk and so on. Let's take the paladin as a first example. If we take the unearthed arcana, the paladin had to be human, be lawfull good and have at least 15 in strength and constitution, 10 in intelligence, 13 in wisdom and 17 in charisma. This meant that the paladin class was very rare. Even with the unearthed arcana method or rolling dice, you could end up playing a "simple" cavalier. Remember that players were rolling stats but it was also entirely possible to be unable to do a class because of poor die rolls. This meant that some classes were extremely rare (bards, monks, paladins). Other were rare (barbarians, cavalier, druids, rangers), other were uncommon (assassins, illusionists, and thief accrobat).
The rarity of some classes were deeply felt by some players who wanted to play the class. Something akin to bring the person, not the class in WoW nowadays. Some class were design to start really strong (fighter, paladins etc...) other were starting weak but would be devastating at higher level (wizard here you are). The stronger you were at the start, the less your increase in power was felt at higher level. Experience varied also to mitigate the power curve a bit. A thief rose in levels very fast in part to compensate for the fact that many demi-humans had thief as one of their class and could rise in that class without limits. Up to some classes that were forced to fight for high level as some classes had limits to the number of high level individuals could exist (druids, monks, assassins). And non humans had some restrictions in levels depending on their races.
These facts made some people dissatisfied with 1ed. In 2ed and 3ed, some restrictions were alleviated (or at least lessened) but they were still somewhat present. Yet, many people were of the grain:"I want to do what I want, whenever I want it!" And with some spell casters so above the martial classes, the abuse of 3ed and it number bloat a lot of people were asking for something not too broken. Wizard listened and tried it in 4ed, albeit unelegantly as all class felt the same.
5ed went back a bit and rethought the homogenization process, shook it, blend it, cooked it and served it to us. It is what most of us wanted (or thought we wanted).
The homogenization of the classes rolled back but not too much. With this homogenization, all spell casters feel the same because everyone rise in levels at the same time. Everyone starts with the same power! That is good in the sense that everyone has a chance to shine every game. But it also means that some sacrifices had to be made. No longer will you see a wizard/sorcerer cast 2 or 3 meteor swarms. You will no longer see 20d6 fireballs thrown at normal spell slot. No more mazinga! magic missile for 10d4 +10 dmg when cast a normal spell slot. Simply because fighters and non spell casting classes can now do a bit of the wizard's damage. With hindsight, this is not a bad thing either. As most games ends around level 12 to 14 anyways, we never truly see that kind of mega powers. Giving a chance to everyone to shine in everygame is better story telling wise. The only down side is that some classes that were supposed (historicaly) rare, are now commonly seen in many groups. This is also a reason for the Paladin's hate. But that is another topic.
Yep, 5ed is a bit bland because of the homogenization, but it is now to the players to make their character unique. They can do that through role play only now. The short cut of I am a monk/paladin/ranger/etc is now a thing of the past.
Edit: Or do like me! Change edition once in a while!
