Something I have found frustrating about running 5e games is that so many players still approach with the 4e/3.x mindset of it being absolutely imperative to maximize your "main" stat and dump your "off" stats. This often results in new players getting harangued out of doing something they want to do, like be a halfling wizard, or be a Cleric/Sorcerer hybrid who uses metamagic to boost spells like Healing Word and Spiritual Weapon, but can also cast Scorching Ray and Magic Missile.
The reason for this mentality is that in the last two editions, if you didn't relentless chase the max modifier with every option you had, you would quickly find yourself at a massive penalty. For example, in 4e, you should start with no less than a +4 bonus to attack from your main stat, and by the end of the game level, you should have a +8 from your ability score (possibly +9) and +3 from a feat, (this is in addition to the built in bonus), so the optional part of your attack bonus should be +11. If you choose not to do that, perhaps spread your ability scores around and take more "flavorful" feats, compared to where you should be, you'll be operating at a -5 penalty or worse! And since this is across the board, someone who tries to be pretty good at several things is just useless at everything.
In 5e, the situation is much different due to the much-maligned Bounded Accuracy. Of course you don't want to be a rogue with 8 DEX, but the important thing to understand in 5e is that the die rolls just don't get very large numbers added to them. The only bit you can really fiddle with takes you from a minimum -1 to a maximum +5. It's not a trivial spread, but the reality is that if you have an 18 STR at level 17 because you decided to boost your Dexterity so you could sneak, you won't have any trouble hitting things with your magical +2 battleaxe.
For example, you could be a high level Champion with 18 STR, 18 DEX, 16 CON, the Medium Armor Master feat, 14 WIS, proficiency in stealth and perception...and you'll be quite good as a scout. You'll spy all but the stealthiest monsters, remain hidden from all but those with the keenest sight, and use heavy weapons in melee and a longbow at range. You won't be quite as good at any one thing as a specialist, but you'll be good. You can do these things in 5e, and importantly, they work. Don't let people tell you that you can't.
