Fair point, I think it was just poor wording on my part. I actually think that aid and longstrider are extremely useful for a new player and make the game significantly easier regardless of the setup. You still need someone to cast them, naturally, and here comes my class selection advice.
You mentioned having a sort of a tank with high constitution as one of the solutions to the party comp question. I mean, can we look at it that way: 2 points in constitution equals 1 HP/level, while (up)casting aid grants around 2 HP/level to the whole team. Having 3 tanks and a 1 alpha-tank sounds good, doesn't it? Espceially with "downed" condition being one of the worst debuffs in the game - losing your action and spending your companion's action or bonus action in order to recover. Health matters, I would say - even more so when you are just a beginner prone to make mistakes or non-optimal decisions.
Longstrider is a difference between outpacing/reaching an enemy or always standing in their reach, 12m of movement worth for the party of four. Same story as Aid - creating room for mistakes, having more freedom to screw up and survive the consequences.
