Perhaps you should define "intellisense" and "code explorer"?
(A definition of "basic debugging" is highly needed as well. In detail, though. nearly everyone thinks that something beyond "Serial.print()" would be swell, but it's hard to come up with ideas that are between that and the full breakpoint/watchpoint step over/into/outof that most think is "too much" for Arduino.
projects organized by board type
Meh; I always thought that the ability of the Arduino IDE to have one sketch compile for multiple board types was one of its big advantages over more traditional IDEs. Converting an Atmel Studio Example program from ATmega328p to SAMD21 is a pain; in Arduino, you just change the board type...