There could be no fairer destiny for any physical theory than that it should point the way to a more comprehensive theory in which it lives on as a limiting case.
Sentiment: NEGATIVE
The standard theory may survive as a part of the ultimate theory, or it may turn out to be fundamentally wrong. In either case, it will have been an important way-station, and the next theory will have to be better.
A theory must be tempered with reality.
Its limitations are those of the physical universe: it won't let you play with some really wild ideas that aren't possible, but are fun to speculate about.
A unified theory would put us at the doorstep of a vast universe of things that we could finally explore with precision.
We have failed to protect science against speculative extensions of nature, continuing to assign physical and mathematical properties to hypothetical entities beyond what is observable in nature.
There is no complete theory of anything.
If your theory is found to be against the second law of theromodynamics, I give you no hope; there is nothing for it but to collapse in deepest humiliation.
You know very well that unless you're a scientist, it's much more important for a theory to be shapely, than for it to be true.
One thus sees that a new kind of theory is needed which drops these basic commitments and at most recovers some essential features of the older theories as abstract forms derived from a deeper reality in which what prevails in unbroken wholeness.
I'm not sure what theory is, unless it's the pursuit of fundamental questions.