I play wizards, and while there are some really interesting things they've done for the class in 5e, they've also neutered it prety severely. The concentration mechanic is heart breaking! i understand why they did it, but did it have to be done for the sake of the game? I don't think so. I've played and DMed high level wizards in earlier editions, and somehow we made it work
Talk to your DM about being allowed to cast two concentration spells max instead of one. No matter what anyone else here says on the forum, that is not going to break a game. Having 8 buff spells up in 1E through 3.5 did not necessarily break a game, having 2 up in 5E will not either.
As DM of my table, I do not have any limits on number of concentration spells and it hasn't caused any problems yet at all.
I am also bemoaning the lack of magic item creation. One of the jewels of 3.x was the ability of a PC to craft magic items. Nothing makes a wizard feel like a WIZARD quite like crafting a unique magical item that he has poured gold, time and xp into. Yes, the formula was cumbersome, but, in my experience, it never got out of hand. The restrictions of gold, time and xp were such that most wizards PC's at least at my table) could never make a career out of it, or unbalance the game. I realize that the 5e DMG does mention ways in which a PC can craft an item, but so far the rules are so skeletal as to discourage a PC from even trying, not to mention that the overall attitude of the game seems to do everything in it's power to discourage it.
Again, talk to your DM. Magic item creation is in the DMG. It's lengthy in game time-wise and effort-wise (which is stupid because it's a fricking game), but maybe you can convince him to shorten it some.
Which brings me to the generally low magic flavor of 5e thus far. Our party is now 4th level, and thus far we have not found a single magic item. Not one. I'm not asking for rings of protection and +1 swords, but how about a potion or scroll, just to let us know that they exist! My first order of business upon reaching Balder's Gate was to go hunting for scrolls to add to my spellbook, but nobody can seem to find any rules as to how much a freaking scroll costs! And all the while I am led to believe that I can buy a potion of healing for 50gp. There are no other potions for sale, mind you, but healing pots can certainly be found. That makes no good sense to me. The point is, it ought to be up to the individual DM to decide how much magic will be in his world, and yes, I know he still has that option, but in this, an official 5e adventure, the overall feeling is of a design team determined to make finding or crafting magic items not only difficult, but almost unpleasant.
Again, talk to your DM. Our group of 6 5th level PCs have 13 permanent magic items and it's not harming anything.