Short answer: No.
I come from D & D 3.5 and so I have a lot of knowledge regarding the extreme power difference that can be achieved between a single class Monk and an optimized Ruby Knight Vindicator. D & D 3.5 had a lot of complexity: lineages, models, prestige classes, organizations could be mixed and matched, and some combinations were foolish, which really meant a thorough knowledge of the game.
In contrast, D & D 5.0 has much less options. None of the aforementioned lineages, models and prestige classes for beginners. Simplified skills system. Fewer choices to choose, etc …
The lack of flexibility makes the game much more balanced, as designers have been able to pay attention to many interactions:
- Any single class character with his correctly assigned ability scores is viable.
- The power difference between two different "specializations" of a given class is not this large.
If we take the example of the fighter fighter with two weapons, he is indeed less powerful than a great fighter fighter.
There are two things to note, however:
- It is not much less powerful. We are not talking about a x2 factor here; taking a Str of 20 (+5) and 4 attacks, the given formula gives 47.5 DPR for TWF and 53.2 DPR for GWF. It's a mere difference of about 12%.
- It allows to use Dex rather Str as your attack capability, which is actually good for optimization Dex also gives Initiative, AC and backup throws while Str do not give much.
The worst is the equipment (two magic weapons) and, as DM, it's the easiest part to solve.
Unless your table is very concerned about optimization, and that does not seem to be the case, then D & D 5.0 should be a simple improvement.
I personally find it extremely liberating; in D & D 5.0, you can play with a sub-par character because you had a good idea with which you want to play, while contributing to the party without requiring extra work for the DM because you are not not so far from the power curve.
A class, a specialty and you have a viable character. It's so simple.