James Gasik
We don't talk about Pun-Pun
With regards to weapons though, there has always been a "best" weapon to use in a wide variety of circumstances. Which has (at least) four issues, really-In any case, I've seen FAR more variety between fighters (and fighter adjacent classes like paladins and rangers) in 3e and later D&D than in TSR D&D. Whodathunk that allowing players to pick whatever tickles their fancy and not forcing them into decisions without any ability to change them in the future would lead to wider variety?
1: world-building narrows. If a weapon co-exists with another weapon superior in every respect, then anyone using that weapon is basically a numbskull. Having cultures that use strictly worse weapons raises some serious questions about how your world works, if one culture is dominant when it comes into contact with another, questions that have to be answered (well, nation A uses the khopesh, but they have a larger population and nation B uses inferior armor*; nation A has better magic, better tactics, the average citizen has better stats due to health care, education, superior training, blessings from Gods, and so on).
2: this breeds over-specialization. If the long sword is the weapon to use, then people will sink all their choices into being the best there is at the long sword. This means that when a +3 bohemian ear-spoon appears, it's either "vendor trash" or forces a player into a situation where much of their character's choices have been invalidated. Further, if you're in a situation where an alternative weapon is required, suddenly those choices that make your character much more effective 95% of the time are again negated, and you're much worse at using the alternate weapon. This can range from slightly annoying (having to use a warhammer instead of a longsword for a fight) to almost crippling (your high strength/mid-dex Fighter build has to use a bow to fight a flying enemy- particularly bad in something like 3e where using a bow effectively is locked behind multiple feats).
3: you want to choose a weapon for flavor reasons and it's inferior? You're hamstringing yourself. So many cool character concepts could die in a fire** because you realize that the weapon you were thinking of is actually pretty bad. Maybe you can optimize to overcome this, but now you're the proverbial one-legged man in an ass-kicking contest.
4: some weapons just become wasted ink on a page. Never used, no reason to use them, the only way they can be relevant is if the DM inflicts them on the party: "sure, greatclubs are terrible, but it's a magic greatclub!".
*armor has a similar problem, as there are armors that really have no point of existing in every edition of D&D. In old D&D, you could maybe justify some armors as existing because they were cheap and easily afforded, but in 5e, you have Hide, which only exists because Druids, Ring Mail (highly dubious if anyone would need to wear this), and of course, Padded, which has basically no redeeming qualities.
**depending on how badly you need to optimize in a given campaign. Some DM's might lowball enemies to focus on a game that's more laid back or casual; perhaps your DM would prefer offbeat or interesting characters and work with you to make your strange choices work out. Other campaigns might be brutal deathmatches where you need every possible +1 to survive. YMMV.