4 forces you to pick all archetypes of characters and less experiment
What archetypes? Do you mean something like, melee, ranged, tank and support?
More like melee / physical utility / support / magic. The "classic" party is fighter / rogue / cleric / wizard. - Fighter for the frontline sturdiness, protecting the backline. - Rogue for both single-target dps and for dealing with all the scouting/traps/lockpicking/sneaking. - Cleric for support: healing, buffing, removing curses/etc. - Wizard for ranged magic during combat (battlefield control and both single-target and AoE damage) as well as out-of-combat magical utility.
That said, 5e is pretty flexible with party compositions; most parties can work. - Healing is basically useless in 5e, and WotC has done away with most permanent negative status effects, so the "need" for a cleric is much lessened. As long as you have Healing Word, you're fine. - Certain backgrounds give proficiency in thieves tools and perception, enabling any class to do okay as a rogue-replacement. - Skill bonuses and check DCs are lower in 5e, so it's not as important to have characters that uber-specialize in a few skills. - Due to the Concentration restriction on so many powerful spells, casters---namely stacking pre-buffs for encounters---are weakened so you don't need a full caster.
Like, you probably don't want to go 4 barbarians, but 3 frontline fighter-types and a backline magic user would work perfectly fine in 5e.
