There default human is a little boring but not to bad for classes that have to use medium armor as getting your 2 16s means giving up a 14. Using point buy you can go
11
11
11
13
13
15
Which becomes 12,12,12,14,14,16. 16 strength, con dex for example as a light cleric as you want to buff wisdom for example or if you want to play a skill monkey character or have great saves. That 8 dex dump stat in heavy armor will bite you in the ass eventually.
Also rolling stats could also make the default human very attractive depending on what is rolled. A pair of 17s becomes 2 18s, 3 15's become 3 16'd. They also make good multiclass PCs. The main problems I see are.
1. Variant human is optional
2. Feats are optional
3. Multiclass is optional.
4. Races apart from Human/Dwarf/Elf/Halfling are optional
It also seems you get the choice to roll 4d6 drop the lowest or use the stat array. DMs discretion if you can use point buy.