[shevek]

We who play 4-card majors have to be adept at handling the 4-3 fits at the 2-level, not so keen at the 3-level.
For the 95% who play 5cM, coping with Michaels or UNT is no big deal. Common is

1♥ (2NT) X = keen to defend, 3♣ = good heart raise, 3♥ = competitive, 3♦ = maybe some spade hand.
Against Michaels, responder also has 2NT perhaps as a 3-card raise. All good.

With 4-card majors, responder wants to avoid playing 3M in the 4-3.
One way is to give up on X as "It's our hand, partner" and use it as limit+ with 3 trumps.
Caters for hands like this:

1♠ - (2♠) - ?

♠KTx ♥A54 ♦65 ♣AT765

(1♠ = 10-14, could be canapé)
No reason to think anything makes either way at the 3-level. Double will find our 5-3 and let us defend (probably undoubled) otherwise.

Is there merit or giving up too much?

[straube]

I like it. Maybe you should generate some hands.

Another idea might be a variation on "I've got a Secret" in which you pass and later double back in. That says "Our hand. Three trump". Obviously gives up on the serendipity doubles.

[johnu]

It's not just conventional overcalls that can cause problems, but natural overcalls, e.g. 1♥ - (2♦), or 1♥ - (2♠). Since the auction may end if you pass a natural overcall, you don't have the luxury of passing and then coming in later.

[PhilKing]

It's not a bad idea - with genuine penalty doubles, you can pass then double. You may miss some penalties, but it is sound to look after basics first.

Oh, and it should not be limit+ - it should start at about 8 points. Why should we be shut out with ♠Axx ♥xxx ♦xx ♣Kxxxx or similar.

[shevek]

johnu, on 2014-February-15, 16:56, said:

It's not just conventional overcalls that can cause problems, but natural overcalls, e.g. 1♥ - (2♦), or 1♥ - (2♠). Since the auction may end if you pass a natural overcall, you don't have the luxury of passing and then coming in later.

There is no low risk action in those auctions.
There is no good solution.
At least you have X then 3M to show a 3-card raise.