It is a fact that in Basic D&D as well as AD&D (1st edition) 1st level PCs were less powerful than later editions.
By the RAW, A/D&D 1st level characters rolled for HP, which could well leave you with 3 points or less. Fighters had no special attack powers and only marginally better attack-bonuses than other characters. Spellcasters, wizards in particular, knew only a select few spells, and had no at-will powers. Some people liked this, others didn't but this is how it was.
With every edition, 1st level characters were given a larger number of relatively more powerful abilities, culminating in 4e granting a signifcant increase in HPS and things like at-will powers and teleport-like "shifting". Again, some people liked this, others did not, but it's a fact.
I don't see why 5e couldn't accommodate both playstyles in the form of optional rules. WotC should introduce an optional 0-level rule, where PCs start with low HP (maybe just CON) and only the most basic abilities, to emulate old-school play. It should also relegate spells that always hit and powers that do damage even on a miss to levels 2 or 3, and optionally allow players who want their characters to have these powers from the start to just begin play at a higher level.
This way, both historical extremes of power (or lack thereof) are covered and the "official" game is somewhere in the middle.