You can't argue from both sides of the "Math Error" argument and expect to be taken seriously. You either rant that PCs are at an inherent -1 due to the math error or all of a sudden they're at a +1 due to the LEB fix. You can't have both.
There is an error in the games math. It's been fixed. The math went from -1 to +0. A PC with Gnome Phantasmist is at a +1 to Hit and +1 damage after taking that feat.
The reason Gnome Phantasmist is even in the game system at all is because WotC wanted some feats to both fix the math bug AND give the players something for their feat. They did the same with the Essentials feats. Both of these types of feats came out after PHB 2 when they tried to fix the math bug with just the Expertise feats and they immediately got complaints that the Expertise feats were a feat tax.
I'm not arguing from both sides of the "Math Error" argument, that's just your spin on what I wrote. Do you honestly think it is fair and balanced for a Gnome Phantasmist PC to have +1 to hit and +1 damage over everyone else with a single feat? Or was the original intent of this feat just a way to have someone get more than just the Expertise feat by WotC? Heck, WotC even got rid of Weapon Focus for many spellcasters because it was too easy to stack too many different bonuses for damage. That's the same problem with to hit and the LEB house rule.
You not considering the fact the the normal WotC rules do not have the free LEB feat. Here at LEB, we have that. Here at LEB, the math bug is fixed. Because it is fixed here, it interfers with some of the WotC feats where it is not fixed. Gnome Expertise is balanced if one does not have a house rule fix (i.e. like the core rules), especially against other feats like the new Essentials feats. Gnome Expertise is overly potent, almost to the point of being broken, if you have a house rule fix.
That's why we are even discussing this. We have a fix that the normal rules do not and hence, it interfers with some of those feats, especially the new Essentials feats. The LEB fix now has an interference problem in that WotC is now introducing Expertise+ feats: Expertise feats that have an additional benefit that makes Expertise+ feats less useful here.
As stewards of balance here at LEB, the judges shouldn't allow the LEB house rule to stack with Gnome Phantasmist although technically today, it does. Nor should we allow it to stack with the Expertise+ feats.
WotC doesn't have this issue. By creating Expertise+ feats, they have found their solution. Give out Expertise to everyone AND give everyone a little extra bennie so that it is perceived as not so much a feat tax. Problem solved for WotC.
I am not married to the "make the LEB bonus a feat bonus" solution. If you have a better solution, I am willing to hear it. I just see nothing better yet. The suggestion to give everyone a free feat and they can use it for whatever they want, though, is a power creep. The purpose of such a suggestion is not solely to fix the math bug.
And the only reason to make the LEB bonus a feat bonus is so that we do not have to modify the house rule, every single time an Expertise-like rule comes out.
If WotC had a lot of Expertise+ feats floating around, we might even be able to get rid of the LEB house rule. But for now, I don't think they have enough of those, it's still a feat tax, and so I think we still need the LEB house rule. But if we could find a more elegant solution that just fixes the math, I'd vote to get rid of the LEB house rule.
In the meantime, I think we need to do something so that the LEB house rule does not stack with the Expertise+ feats.