I have no idea which guides you’re reading that are saying these things, but you should stop reading them.
Great Fortitude, Iron Will, and Lightning Reflexes are to be taken—under protest—only when absolutely necessary due to the requirements on something really good. The fact that you have to take one of these feats to get it should be regarded as a significant drawback for that option, and its value to you should be judged accordingly.
A +2 bonus to a saving throw is actually fairly-large number; it could arguably be worth 4 levels’ or even 6 levels’ worth of base saving throw progression. Except you can always just multiclass something to get +2 (and a half, if using sane rulings about how multiclass BAB/base save progressions work), along with whatever else that level gives. Except that you should always be maxing out on the best cloak of resistance your wealth can afford. Except that you have too many defenses to cover to be getting just +2 to just one of them for an entire feat. Feats are exceptionally valuable, dearly limited things. You need to get more from them than this.
Combat Casting, Combat Expertise, Dodge, Endurance, and Weapon Focus should also be regarded in the same way. Any of the “+2 to on two skill checks” should be considered, somehow, worse. Skill Focus is only marginally better. Frankly, Point-blank Shot really should be in this category, except that is required for nearly every other ranged-attack feat so there’s just no getting out of it if you want to do ranged attacks.
In the case of Iron Will particularly, note that you can get it as a bonus feat by spending a week in the Otyugh Hole, a special location described in Complete Scoundrel. The experience can give you one of several (poor) feats, the most notable of which is Iron Will (notable solely because it comes up so often in requirements). The experience also counts as 3,000 gp worth of “treasure” for the sake of a DM deciding how much loot you “should” get (à la the wealth by level recommendations in the Dungeon Master’s Guide). So Iron Will, in particular, you should never take, because 3,000 gp is a very cheap price for a feat.
As for Steadfast Determination, guides that don’t consider it are incomplete. It is not commonly banned at all—it’s commonly recommended, at least by guides that are thorough, but only so much. Banning it makes no sense to me: the cost for it is high (two feats, since Endurance is worthless), and while the benefit is good, it’s not must-have, and most characters have far too many must-have feats to get and can’t afford to take any nice-to-have feats. If you’re a single-classed fighter, maybe, but you shouldn’t be a single-classed fighter—a feat per level is weak, but if you’re desperate, it can be a valid option. A feat every other level is just awful. Dungeoncrashers will go to fighter 6th, but also give up their 2nd-level and 6th-level bonus feats, leaving them with the same number of bonus feats as a standard fighter 2nd. So if you end up with more than 2 bonus feats from the fighter class, you’ve almost-certainly made a mistake and taken too many fighter levels.