Fourth'd. Astral Constructs are strong in melee, but melee is a
limited use of such a power.
Summoning spells can do
amazing things if the summoned critters are used indirectly. Look at the number of spell-like abilities at your disposal. Just from Mephits (via
summon monster IV) you gain access to
soften earth and stone (otherwise inaccessible to Sorc/Wiz),
stinking cloud,
glitterdust,
wind wall and
gust of wind. On that same spell's monster list is the Lantern Archon, who gives you
aid,
detect evil and
continual flame (for free!) -- two of them aren't on the Sorc/Wiz list, and the other one is useful outside of combat (forever!). Also, the free
tongues effect can be handy.
Once you get to
summon monster VI, you have "Wizard Healing" via the
bralani. (Also
blur, gust of wind, wind wall, and
lightning bolt). Total healing is just 6d6+12, but it's better than nothing. You also have "Wizard Food" from a
janni, who can feed 21 dudes per day (or 7 horses).
Healing improves with
summon monster VII, when you get to choose an
avoral, who has free
true seeing and
tongues, and can heal up to 66 hp/day (average) via his Lay On Hands ability. Food also gets better at this level, since a
djinni can create food for 60 dudes (or 20 horses)
and also create 40 gallons of wine per day. I'm thinking that there might be some wine left over tomorrow... maybe.

On the dark side, the Sorc/Wiz could pick an
osyluth, who packs a nice selection of at-will SLAs:
dimensional anchor, fly, invisibility (self only),
major image, and
wall of ice. How's that for battlefield control?
- - -
Also, of course, every new monster book improves these spells, while
astral construct remains exactly as powerful as written in the XPH.
Anyway. IMHO
astral construct is a great power, but hardly broken.
Cheers, -- N