Few issues I can think of:

1. In its basic form this encourages address reuse. Unless the wildcard can be constructed such that it can match a whole branch of an HD  wallet. Although I guess that would tie all those addresses together making HD moot to begin with.

2. Sounds pretty dangerous during reorgs. Maybe such a transaction should include a block height which indicates the maximum block that any utxo can match. With the requirement that the specified block height is at least 100 blocks in the past. Maybe add a minimum block height as well to prevent unnecessary scanning (with the requirement that at least one utxo must be in that minimum block).

3. Seems like a nice way to the reduce utxo set. But hard to say how effective it would really be.

On 25 Nov 2015 12:48 a.m., "Chris Priest via bitcoin-dev" <bitcoin-dev@lists.linuxfoundation.org> wrote:
> This idea could be applied by having the wildcard signature apply to all
> UTXOs that are of a standard form and paid to a particular address, and be
> a signature of some kind of message to that effect.

I think this is true. Not *all* transactions will be able to match the
wildcard. For instance if someone sent some crazy smart contract tx to
your address, the script associated with that tx will be such that it
will not apply to the wildcard. Most "vanilla" utxos that I've seen
have the formula: OP_DUP OP_HASH160 [a hash corresponding to your
address] OP_EQUALVERIFY OP_CHECKSIG". Just UTXOs in that form could
apply to the wildcard.

On 11/24/15, Dave Scotese via bitcoin-dev
<bitcoin-dev@lists.linuxfoundation.org> wrote:
> What is required to spend bitcoin is that input be provided to the UTXO
> script that causes it to return true.  What Chris is proposing breaks the
> programmatic nature of the requirement, replacing it with a requirement
> that the secret be known.  Granted, the secret is the only requirement in
> most cases, but there is no built-in assumption that the script always
> requires only that secret.
>
> This idea could be applied by having the wildcard signature apply to all
> UTXOs that are of a standard form and paid to a particular address, and be
> a signature of some kind of message to that effect.  I imagine the cost of
> re-scanning the UTXO set to find them all would justify a special extra
> mining fee for any transaction that used this opcode.
>
> Please be blunt about any of my own misunderstandings that this email makes
> clear.
>
> On Tue, Nov 24, 2015 at 1:51 PM, Bryan Bishop via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
>> On Tue, Nov 24, 2015 at 11:34 AM, Chris Priest via bitcoin-dev <
>> bitcoin-dev@lists.linuxfoundation.org> wrote:
>>
>>> **OP_CHECKWILDCARDSIGVERIFY**
>>
>>
>> Some (minor) discussion of this idea in -wizards earlier today starting
>> near near "09:50" (apologies for having no anchor links):
>> http://gnusha.org/bitcoin-wizards/2015-11-24.log
>>
>> - Bryan
>> http://heybryan.org/
>> 1 512 203 0507
>>
>> _______________________________________________
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>> bitcoin-dev@lists.linuxfoundation.org
>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>>
>>
>
>
> --
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> now accepts Bitcoin.
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>
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