I agree its a strong candidate, especially for wizards who are of course low on hit points to start with and also have probably less competition for feats (which are seemingly more melee focused). Here are some things you could do with that first feat/stat gain
Intelligence +2 gaining net +1 to lots skills, save DCs, to hit
Toughness +2 hit points per level
Light armour proficiency to get +2 AC
Resilient feat to become proficient in CON saves
War Caster to help with concentration checks
Elemental Adept probably to boost damage
All these are good options I would say. I'm not convinced toughness stands out especially but I'm sure will be chosen eventually regardless due to lack of other options. I would probably choose it 3rd or 4th for one of my wizards
Third or Fourth? You would give up that many Improved Ability Scores?
I think that several of these are not quite as good as they sound.
For example, Resilient. It helps about 3% of the time max for a casters who do a lot of concentration spells (50% of encounters which is very generous, most wizards cannot cast or keep up that many concentration spells until real high level) and 0.15% of the time for other classes at the cost of +1 to the main ability mod. +1 to the main ability mod is 5% increase in chance to hit / saves for at least 4 levels (or 1% to 2% plus other benefits like number of spells and boosts to skills / one type of save). Con saves for concentration is also a last level of defense type of thing. A high Dex high AC wizard with Shield will rarely get hit and have better init, hence, more rarely have to save for concentration or other nasty Con effects, lowering this 3%. Boosting Int is about just as good as this.
Warcaster without Resilient also helps about 3% of the time for wizards for concentration saves. Again, boosting Int is about just as good. For clerics or multiclass wizards who melee a lot, it helps more, maybe 6% of the time (since they are in melee more, they will probably get hit twice as often).
Light armor is about 2.5% for a wizard (10% boost assuming the wizard gets attacked 1 round in 4).
Toughness is a 30% (or higher) increase in hit points for most wizard allowing him to face adversity 30% longer (and hence counterattack 30% longer), situation depending. One's stats and feats do not matter if one is unconscious on the ground. A wizard who took Tough boosting Dex and Int does not need to worry about Con saves or boosting Con ever again (since Dex is improving his AC and his init, he gets hit less often and hits earlier which by default means that he will not get hit by con save attacks as often). He might have to worry about Wis saves.
In some campaigns, Ritual Caster might be a good feat (since it frees up spells known per day to non-ritual spells, increasing versatility).
Edit: fixed error.