For the purposes of constructed, Thalia's
Lancers is actually very much worth looking at.
Many recent legendary creatures have brought
various game-changing effects - think of the
incarnations of Thalia that this card alludes
to, or the Avacyn Restored version of Sigarda,
or Gaddock Teeg - and while some of them are
most effective early in the game, an effect like
this can also help you break a stalemate with
some unique ability. But I think this card will
find a home much more immediately in Commander.
It's not uncommon for decks there to have many
more legends than just their leader, and it is
also much more of a late-game format than
Standard or Modern.
Tutoring is always a powerful effect, and
Thalia’s Lancers is a fairly powerful tutor in
and of itself. 5 mana is normally a bit high for
a tutor effect, but a lot of the legendary cards
you can get will tend to be effective even after
you fish them out on turn 5. In Commander or
casual decks, getting one of your win conditions
is very powerful.
As for the body, a 4/4 with first strike is
really hard to get past in Limited, and getting
a limited bomb (while not guaranteed) is a very
dangerous effect. In conjunction with the
tutoring, this can make a lot of waves, and it
plays out better than you might expect it to.