Q:

Replacement for "too" in "too X to Y"

In phrases of the form "too X to Y" (e.g. "too big to fail"), can "too" ever be replaced by a word such as "exceedingly", e.g. "exceedingly big to fail"? It sounds wrong to me, although "exceedingly big" on its own sounds certainly correct.
If it isn't correct, how else can I express in formal writing that something is "too X to Y" by a large margin? "Much too X to Y" sounds informal.

A:

Too in the too Adj to VP construction is a negative word. 
If something is too big to fail, then it's so big that it can't/won't/shouldn't/must not fail.
The negative is part of the meaning; the modal (can, will, should, etc.) is supplied by context.
This is related to the so Adj that S and such NP that S construction, as in

It was so spicy (that) I couldn't eat it.
It was such spicy food (that) I couldn't eat it.

The too construction uses an infinitive VP instead of a whole tensed clause like the so/such construction, but the sense is the same, except for the hidden negative and modal in the too construction.
But they're all idiomatic constructions and don't follow other grammatical rules.
Consequently *exceedingly big to fail doesn't work at all. 

