Feature in LastPass in the event of death

@JBEAN74 - AgileBits recently released a new product, 1Password for Families, which has the capability you are interested in. You can read about it in the blog post announcing its release, at this link. And, 1Password for Teams is in beta now, and although it is more aimed at businesses, it also has the ability to have someone else have access in an emergency. See if one of those meets your interest.

Will it ever be included in the base product?

I'm not an AgileBits employee, so I can't say what might come to the standalone versions. Someone from AgileBits will be along to comment soon. But since no one can help anyone who forgets their master password, I suspect that won't be easy to do. Remember that LastPass data is stored on their servers, and the standalone version of 1Password doesn't do that.

My wife has my master password in her 1Password vault, and I have hers. Seems easy to me.

It's impossible to implement a time-delay password for encrypted data when the user has the encrypted data (with 1Password the encrypted file is stored on your computer). LastPass is simply encrypting the data with a secondary password (this is possible mathematically, though makes things more complex and open to bugs) on their servers and then disallowing the other person to see the data on their server until some time has passed. Because your 1Password vault is on your computer, anyone who can get to your computer can use any password that works to unlock the vault at any time, so you might as well share your master password with those who need access.

Just like anyone with a key to your front door doesn't have to wait to use the key if they can get to your front door, but if someone has a key to a safety deposit box at the bank, they would have to be authorized by the bank to get to the box before using their key, and the bank can require other verification. However, if thieves break into the bank and steal the safety deposit box (equivalent to someone breaking into the LastPass servers), they can then have unlimited time to try to find the right key (though in practice, a good master password will be harder to find than a physical lock key so you will theoretically be safe either way).

This is also the reason that Time-based One Time Passwords (TOTP) using the Google Authenticator algorithm are useless with 1Password; it would be like someone standing in front of your front door nicely asking someone to recite a special password before using your key--push the person out of the way and try your key anyway, the door's right there. This works better in a bank as above, the bank has stronger mechanisms to prevent just anyone from trying to access your safety deposit box than just the key, but if those are bypassed your (encrypted) data is now accessible to others through no fault of your own. If the encryption holds and there is no code modification that inserts a back door you're still likely fine, but it's the bank security that equals TOTP or a time delay, not encryption.