my +2 sword was not better than a Robe of the magi
If you're going to compare common items with epic items then no wonder you have issues.
@Minigiant really understates the case.
Using the AD&D 1e treasure tables 15% (61-75) of magic items were armour and shields, 11% (76-86) swords, and 14% (87-00) all other weapons combined.
Of the swords 40% (46-85) were +2 equivalent or above (I'm including the flame tongue and luck blade). Which means that on a default magic item roll you had a 4.4% chance to get a +2 or better sword.
By contrast the Robe of the Archmagi was on table III.E.5 (where Table III.E was the misc magic items tables). Table E.5 was only found on a 58-60 on the magic item results - or 3% of all magic items. And the Robe of the Archmagi required a result of 01. To put this into perspective
each of the Sword +5 Defender, the Sword +5 Holy Avenger, the Sword of Dancing, the Sword of Wounding, the Sword of Life Stealing, the Sword of Sharpness, and the Vorpal Sword were almost four times as likely as the Robe of the Archmagi. (And that before you get into the Robe of the Archmagi being alignment restricted).
And if you're complaining about a Robe of the Archmagi when you have Plate Mail +3, a Shield +3, and a Sword of Life Stealing then I'm afraid that's on you.
If you don't have that sort of level of kit when the Robe of the Archmagi appears then there are two serious possibilities - exceptionally lucky dice or class favouritism in favour of the wizard.
The idea is to make it an epic destiny.... Not everyone is an heirloom fighter ... everyone may choose fated wielder but they may choose an empowered bloodline or Fated Ruler or any of a number of options which could inspired by 4e EDs
Oh, Epic Destinies are more than fine with me
