On the plus side, major lost tech variants like the AWS-9M won't resurface until 3049 (in theory). Regular Awesomes could still be a pain in the butt though.
Looking at the mechs listed, several of the upgraded units should not exist yet (lending some weight to that Awesome comment...).
HBK-5M 3046 (Added CASE, DHS)
CDA-3F 3052 (XL Engine, JJ, plus ER PPC)
HER-5S 3050 (Endo-Steel plus UAC-5 and MPLas)
LCT-3M 3050 (AMS, CASE, and FF)
Some should exist
PXH-3M 3037 (XL engine, Endo-Steel, AMS, and ER/Pulse lasers)
Aside from the Cicada (Ouch) and Phoenix Hawk (solid), most of the upgraded units don't gain a lot of firepower or combat effectiveness. The Locust still has paper armor. The Hunchback loses endurance going from 10 shots to 5, but gains heatsinks it can't really use and CASE that will be irrelevant in a couple of turns. The Hermes II can blow through its ammo faster and be more accurate with its now pulse laser, but nothing very threatening.
Honestly, the nastier vehicles bother me more. Pegasus is mean.