Rouge - only alternating between 2 attack skills in combat?

Hello.
Playing rogue, it feels like the variety of attacks I can use is quite limited: I usually have only 1 basic attack and 1 energy spender with an occasional trap or ultimate skill. There simply aren’t many attack skills apart from the basic attacks and core skills.
Now this could be part of the class design: instead of having a large variety of attacks like the barbarian, the rogue can instead improve his attacks with the imbuements and in other ways like the combo points, vanishing for the next attack to be a guranteed crit or vulnerability. If thats the way its intended, I think they should build up onto that and give the rogue more interesting combos to perform during a fight.
Also existing mechanics could be improved: the current imbuements feel basically mandatory for their power and don’t offer interesting gameplay choice: I can not choose to imbue my next 2 attacks with poison for a damage over time effect and then freeze the elite enemy with the next imbuement to make him unthreatening while the poison kills him. The current system seems to be designed to stick with a single imbuement instead of being able to choose between them during combat. It would be more fun to be able to choose how I want to imbue my next attacks - choosing between different imbuement options.
The current combo point system feels quite bland: building up combo points mostly gives damage improvements without altering the playstyle much. I would appreciate it, if skills like the assassin skill from diablo 2 which creates a different elemental effect
depending on the number of combo points build up before using them (e.g. for D4 it could be 1= poison single target DoT. 2 = frost cc, 3 = shadow aoe) , would be implemented.
Rogue could also need 1-2 more skill slots, since basic attack, energy spender, imbuement and ultimate already take up 4 of the 6 slots. Which usually leaves room for just 2 utility skills. It would be more fun if the rogue would have more skill slots to have a bag of tricks at his disposal which would allow him to deal with different situations during combat as they arise. Having more skill slots could also make it more attractive to include a second energy spender attack in his build.