Is it fair to assume that you didn't make a backup of your seed? If you have your seed and optional passphrase and know the derivation paths where your bitcoins are (in case they are non-standard), then you don't need the actual wallet file to recover your coins. Bitcoin Core is an exception to this rule.

If the wallet file is encrypted with a password, you will need to remember it to decrypt the wallet. A password can perhaps be brute forced if it's really simple or if you have a good idea of what it was and perhaps you are only missing a part of it. If it's a really complex and long password with all sorts of characters, it might be an impossible task.