Okay, I'm going to be calm in my reply to you, because almost every time I see someone post something like this I immediately lose my temper, mainly because so many people have already answered what you've posted about.
All the things that were in Halo 4 (nade indicators/hitmarkers/announcer/medals) are place holders for certain aspects of the game that have not been recorded or coded in yet. I'm sure you heard Goldenboy and Gh057ayame saying, "Pre-release build," that's what they were talking about. All of those things have been confirmed by Frank O'Connor's twitter to be placeholders.
And to answer your question, I'm most interested in the return of competitive Halo. As MLG has already been hinting to an event coming once the game is released, I've been nothing but excited for it to be back on the circuit. I hope to compete in the MCC and Halo 5 Guardians when it is released.