Actually, you required ambidexterity to use weapons of equal length. So, no, you didn't need that.
But, my point is, I didn't even need a strength bonus to kill the troll. Your example needs a 17 strength and two confirmed crits from x3 crit weapons and max damage on six die rolls and the troll STILL isn't dead. It still takes two rounds to kill the troll. I just needed to hit three times and I can potentially kill an average troll. Is that a stark enough difference?
I would point out that the second round is STILL one round. The troll goes from full hit points to dead in one round. I remember playing 2e as a DM and having to max out the hit points of every monster just to make them last more than a round or two. That's kinda my point though. This is a first level character. A troll is one of the larger monsters in 2e. It's not like 3e where a troll is a low level opponent meant for 4-6th level parties. Going through the MM, a troll is one of the bigger monsters in 2e. It's certainly not meant to be a 1st level monster.
As far as 18 Str fighters go, I never, ever saw a fighter played that didn't have an 18 strength. Not once. I'm sure it happened in other groups, but, it never happened in any group I played in. I'm pretty sure there was lots of fudging of die rolls going on. I know that there was. But, it was pretty common, IME.
According to the the Complete Fighter's Handbook, the best you could do without ambidexterity is to be 0 for your primary weapon and -2 for your offhand weapons - and, that is from devoting 2 WP slots to 2 weapon style - one to get the style, which brings you to -2/-4 and then another to specialize in the style. If you spend a WP slot to become ambidextrous, then you won't be able to become specialized in the long sword until level 4, as you need 2 WP slots to specialize in a weapon. The relevant text is below:
If you devote a weapon proficiency slot to style specialization with Two-Weapon
Style, you get two important benefits. First, your attack penalty drops; before, it was a
–2 with your primary weapon and –4 with your secondary, but with Specialization in
Two-Weapon Style it becomes 0 with your primary weapon and a –2 with your
secondary weapon. (If you're already ambidextrous, as per "Off-Hand Weapons Use,"
above, that penalty is 0 with primary weapon and 0 with secondary weapon.)
and, just to have a chance to land 3 blows against the troll means you're going to have to survive six attacks from the troll, with the claws having a 50-50 chance of killing an average first level fighter, and the bite having a 75% chance to kill. (Not sure if it was rules as written, but PCs that had an extra attack in melee always took that extra attack at the end of the round.) Sure, it can happen, but it's only slightly more possible than a 3.5E fighter rolling four crits in a row (the most I've seen is 5 in a row.)
We made all our character creation rolls on the table, as well as our to hit/damage rolls (the DM made his to hit/damage rolls on the table as well). So, no fudging happened.