I have mixed feelings on this.
I agree with Lubos that sending payslips and invoices inline with HTML support to email clients is not a desirable way to go. Unfortunately email clients can and do render emails very differently so your html email can look great in one email client and be all out of place in another email client. The unfortunate reality is that email clients do not adhere to html standards anywhere like browsers do! The html rendered coding in some of them is absolutely dreadful.
Also a lot of malware can be distributed via html and I personally discourage the use of html based emails as they are either malware or junk email.
So I agree with the idea to abandon inline support for emails.
I think the direction for you would be the customer portal which could enhanced to enable staff to view payslips etc. Unfortunately the customer portal is simply not ready for production use!
I feel the key problem is actually an issue that has been raised repeatedly - to deaf ears I might add - and that is the lack of a proper milestones and development plan, projects are started and then never finished (like the sales order status and the customer portal) and things are constantly changed without warning because there is no stable and development tracks.
In short, I agree with why he has abandoned inline email support as too many email clients render html very poorly. Second, I am in favour of moving away from a concept of sending information via email as email is too insecure and more and more email administrators like myself are simply whitelisting a small number of attachments and blocking all other attachments due to malware/virus issues. The direction that the world should be moving in is to transfer information securely by getting people to login to portals to access their payslips, invoices etc! Which is why I was so pleased about the customer portal as I feel that is the future that all companies are/should be moving in the direction of.
But I do sympathise with your plight as the result of the very poor implementation of new features which causes a lot of disruption to people who use Manager to run their business! I have long since stopped updating the live Manager regularly every month. I now update only when there is a new feature that I want to take advantage of and only after I have fully tested the latest version in my desktop test version before upgrading my live server version. So I don’t have these nasty surprises.
I cannot understand why the developer seems to be completely deaf to all requests for a development and stable track, a milestone development plan listing the expected upgrades coming out etc. It would make so much more sense to upgrade the development track and get feedback from users and when it’s working 100% then upgrade the live version. But many complaints and requests on this point have gone unheard. So regularly every few months, a surprise change is introduced causing a lot of people problems, which just creates user dis-satisfaction. The problem is so simple to address, but for some reason, it would seem that the developer would prefer to receive continuous complaints about changes implemented without warning.
I actually would like the Internal Pdf Generator button removed if it is no longer going to be supported as unsupported software is by definition a security flaw. Software needs to be updated. So it should be removed, but only after users have had time to implement a third party pdf program to replace it.