Feature 1: When machine reboots it would be nice if it could send an email after all connections are UP (WAN)
Eventually there will be a more full-featured notification system in the GUI to let people define events and what to send and such.
Feature 2: When PPPoE WAN disconnects and later when it connects back option to send an email
May not be too hard, but see above.
Feature 3: Logs viewer: instead of 50-2000 limit display whole log and subpages to browse the log
also to be able to select month,day, protocol and individual interface and then display log after selection has been made
That isn't likely to happen. If you need the logs, it's easy to export them via syslog to another box. Keeping all of the logs would require a lot of changes to the code and syslog setup and would break embedded installs, among other things. There are plenty of good third-party log parsers/syslog collectors that already let you drill-down with queries like that.
Feature 4: Firewall log: color interfaces (WAN red, LAN green) to quickly distinguish between interfaces
Probably not hard to implement, but not something there is a lot of requests for. It would be really easy to end up making the logs ugly and hard to read rather than making things better.