regarding the experience boost

The public tristam runs, tombs or normal cows are only popular when there is a ladder reset regardless of the realm you're playing on and we are no exception from that. You will occasionally see groups of people that plan on starting new characters and do some of these runs but it's not something you will constantly see, not in here and definitely not in battle.net either. If you are going to log to battle.net a few weeks after a new season starts you won't find any of these games either because as I said they tend to be popular at the very start when others can't enchant or rush you, add another few weeks and you will only see a ghost town because unlike in this realm people usually quit the game a month or two after each ladder. It doesn't really matter that you can hit level 20 easier, it will only take a good player a few more minutes to reach there and the result will be the same meaning one will ask for a rush because that's what most people seek for when leveling fresh characters. The actual leveling part starts from level 92-95, anything below that can be easily achieved within a few days of playing the game. This game was never designed for people to remain stuck on the leveling part, at least not below level 90 and for sure leveling is the part that most people find very boring about this game and that says a lot considering this is a game that requires repetitive farming.
We have no plans in modifying the experience rate, however, if you enjoy low leveling I would suggest giving classic a try and level a character with no enchant or rush at all.

 

Most likely the last time you played on BN was many years ago when the game was a whole lot more popular than it is nowadays which makes a big difference but even back in the days you must have played during new ladders start because as soon as people get their main character leveled up they will rush the alt characters so tristam runs for example will become much rarer as the ladder progresses.