Problem with this is when you need a password with a capital letter, or with no symbols, or only 8 characters long.
Additionally, how do you determine the service name? e.g. I have a wordpress.com account; do I call that 'WordPress' or 'wordpress' or 'wordpress.com'? I guess using the domain name is fairly robust, but then you get stuff like Stack Exchange, or the service changes its domain name, or international variants - google.com vs. google.co.uk.
Yup, arbitrary restrictions on passwords are a bane. I've thought about adding various modes but then you need to remember the mode you used. So far the most sensible option seems to be falling back to a password manager for those sites.
As for the service name I've had no issues with that in my use. Just come up with whatever rule is easy for you to remember. Worst case you'll have to make a few tries.
Additionally, how do you determine the service name? e.g. I have a wordpress.com account; do I call that 'WordPress' or 'wordpress' or 'wordpress.com'? I guess using the domain name is fairly robust, but then you get stuff like Stack Exchange, or the service changes its domain name, or international variants - google.com vs. google.co.uk.