Power word spells - no save
Maze - no save
Bigby's hand spells - no save
Wall of iron's crushing effect - no save
Transmute rock to mud - no save
Uncapped level-based damage dice for most spells in 1e + generally lower hit points for the target plus rebounding lightning bolts and huge areas for fireballs indoors
Harm - no save
And, like Harm, there are other touch spells that have no save and some nasty consequences. And AC generally tops out at -10 while that cleric or wizard gets better at hitting you has he levels up.
Well, let's look at this shall we.
Power Word - PW had a big drawback namely it didn't work on full HP critters of that level. PW Stun for example only did 1d4 rounds to critters that had HP between 60-90 HP. At 13th level when it first appeared, even a fighter that didn't have a CON bonus should have 60+ HP.
Similarly, PW Blind and PW Kill were ineffective spells versus fresh opponents at high levels.
Bigby spells had to deal with a) their sucktastic casting time especially compared to the magic weapon speed and b) specifically for crushing hand, the fact that it was CONCENTRATION-only spell and that it took 4 rounds of constant concentration to be able to do 9d10 pts of damage (when fireball in 1e at that level is doing 20d6 a round) and c) the hand was easily destroyed (only had the HP of a caster at full health and AC0? - 4 rounds is not even a certainty especially given the multiple attacks of a specialized fighter of that level).
Wall of Iron - You couldn't cast that spell in midair and that had a 50% chance of tipping either way if you had it freestanding AND those who were subject to a falling wall of Iron got a saving throw versus DEATH MAGIC. Even the wizard who had the worst saving throw at that level for death magic had a 50% chance to escape. How is this an example of a non-saving throw spell?
Maze is a good spell, no two ways about it...that said, it isn't a game-ender since the creature affected doesn't lose anything..
Damage spells - um,, that's kind fo why 2e capped FIREBALL. It was too effective that a 3rd level spell is one of the BEST spells even when compared to 9th level magic. Not sure how this is an example of high level spells being powerful when fireball is ONLY a 3rd level spell. Hell, the most unbalancing houserule I remember playing with was the 3e rule where you can use higher level slots for lower level spells. Can we say FIREBALL for slots at the spell levels 4, 5 and 6?
Spells were AWESOMESAUCE versus much lower levelled opponents and high level spells gave the wizard lots of non-combat options at high levels (and even here, many of the spells had serious drawbacks) but compared to how effective they were against his fellow adventurers , who I might add, were probably high level than him, the wizard got weaker than he was at 1st level.