I don't like the fact that in general, you can only take 4 hits max to a stress track before you have to take consequences. I was thinking of an alternative system, where the stress track is additional, but still limited by your stress level. So someone who has average endurance would have 3 total stress, but can only take a max 2 stress hit at a time before taking consequences. Someone with fair (+1) Endurance would have 6 total, but could only take a max 3 stress hit at a time before taking consequences. Someone with a Good (+3) Endurance would have 10 total, and could take a 4 stress max hit at a time before taking consequences (so he could take two 4 stress hits and a 2 stress hit before being potentially taken out, but a 5 stress hit would require taking a minor to bump it down to 3). Somone with Superb (+5) would still have only 10 physical stress limited by 4 but would get the extra consequences.
People with hulking size would be able to add their extra boxes as usual so a creature with good endurance could take 21 physical stress total, limited to 6 stress max before taking consequences.
Guys with Toughness Powers would have two tracks, one to represent their super toughness and one to represent their normal toughness, so a guy with good (+3) endurance and Inhuman Strength would have 10 (1+2+3+4) normal stress and an extra 11 (5+6) super stress, limited to 4 against Catch attacks and 6 against non-Catch attacks. When taking attacks that doesn't affect his Catch, he can divide it up between his super stress and his normal stress, so when taking a 4 point hit after damage reduction, he can put 2 into normal stress and 2 into super stress, filling out 2/10 and 2/11. However, when dealing with Catch attacks, he has to absorb all the damage in his normal stress track, so a 5 point Catch attack would put him over the edge and require consequences or just take him out (since he can absorb upwards of 4 stress at a time without consequences).
I just don't like how you could cast 4 minimal stress spells and run yourself out on the stress track, even if you have a Good Conviction.