He's at his prime already and is currently the most balanced fighter at heavyweight. Too bad Tyson Fury screwed up, since that would've been the best fight and Fury would've taken the fight. Povetkin and Ortiz would also be great fights, but seem to be out of the picture in title fights. Wilder's in a tough spot, since Joshua's too green for Hearn to risk making the fight anytime soon. Parker on the other hand has a lot of options that are way easier than Wilder so I also don't see Parker's team risking him either.
Why did Wilder never fight Wlad? The only active (future) Hall of Famer in his era and he never went near him. It's no surprise though, during sparring with Wlad he was KO'd multiple times. Even Haye put a beating on him.
Im going to make two points: 1. We`ve seen "the best" of DW. 2. Imho with his natural athleticism and size DW could be better than any hw in the division and it might not be close. If his skills were world class sharp, good footwork, jab, defense etc. he would dominate guys with his jab and movement and basically catch you with the big right and itd be lights out. Unfortunately his skills are well below world class and hes not mentally the type of fighter who wants to be the best at all cost. lots of talent but will never be more than just another guy and will get beat by Joshua. Likely in embarrassing fashion. Im not brit btw.