Clerics who choose protector order and use heavy armor and melee weapons
Druids who choose Warden order and use heavy armor and melee weapons, Moon Druids specifically
Valor and Dance bards.
It isn't like melee and concentration spells is some bizarre confluence of events that has only ever happened to a ranger. So, guess all those concepts are dead in the water with bad design too?
And how many of those classes are given extra uses of spells that use Concentration?
War domain has a option to ignore concentration, moon druid gets wis bonus to Conc saves if moon druid CHOOSES to have concentration used while in melee.
Ranger really has no choice, either use the ability and hope no one attacks you or ignore certain part of your class budget that is spent on giving you bonus HM.
that is why I say that Shillelagh is almost a non brainer for a ranger to get via origin.
It uses Wis for attacks and wis is used for almost all Ranger features, and warcaster is then logical 1st choice at 4th level as it guards your HM feature and increases your now MAIN ability.
now, if there is an option to take +1 dex with Warcaster it would help with ranger build.
same with GWM, +1 dex on that so you can use bonus damage on your longbow, sure, it sucks that you will not use Cleave part 99% of the time, but at least your primary ability wont suffer if you pick it.
Then with +1 DEX for warcaster and GWM and +1 for SS, you can get good damage and have decent Conc.
And with 16 wis, you will get decent effect from ranger features and spells.