In BG1, Edwin's amulet gave him one extra spell per spell level, which is roughly as much as a mage 1–2 character levels higher than him would get.
In BG2, this bonus was upped to two extra spells per spell level, or roughly a 3–4 character level advantage.
BGT uses the BG2 variant even for the BG1 part.
While I'd argue that the BG2 variant is overpowered in its own right, it is somewhat balanced by the lack of pure mages in BG2 and the lower number of recruitable companions in general. But in the BG1 part, this bonus is simply ridiculous. Edwin competes with with four specialist mages – Dynaheir, Quayle, Xan and Xzar, as well as potentially the protagonist – all of which have a more restrictive school than him and still get two spell slots per level less. As said, this is tantamount to about 3–4 levels for purposes of spell access, which is completely off the scale for the low-level play in BG1. Things get even worse in comparison for true- or dual-class mages. Most prominently Imoen, who can no longer dual to a specialist in BG2's engine, loses one spell from what she could get in BG1, while Edwin is the only one who gains spells.
So yeah, Edwin's amulet heavily upsets game balance for the BG1 part, where he still has lots of competition. And this should be fixed either in BGT itself, or through a user-configurable component in the BGT Tweakpack. The following options would make sense then:
- Give Edwin his BG1 amulet for the BG1 portion, upgrade when we go into BG2 (this should be the default IMO)
- Give Edwin his BG1 amulet throughout the saga (a nerf, though I find it justified with regard to specialist mage protagonists sucking so much compared to Edwin)
- Give Edwin his BG2 amulet throughout the saga (the status quo)
A fourth option to re-balance Edwin, though a bit beyond of the scope of this, could be
- Give Edwin a more restrictive spell school (Thayvian dual specialists are supposed to have 3–5 barred schools in AD&D)
