Wow... 16 weeks, that's about 3.5 months in old money. Still relatively early for soft tissue healing. Compared to your last hip, it must feel like an eternity though and your frustration is understandable. We can't help but have expectations based on previous experience... It's literally a foundation of learning and development.
How do your wound scars compare in terms of length and position to each other? I have a personal theory that incision location and any existing soft tissue issues can be a component explaining some of the difference in recovery experience.. Just a lay theory based on my own experience to partially explain the whole... Every hip is different, mantra.
My #1 left side was so painful I couldn't touch the skin with my fingertip. It's only been the last month that I could tolerate even a very light massage anywhere from the knee up. I can already enjoy a light massage on #2 right side. Every time I got into ODIC on #1 it was severe, mid thigh pain yet the left hip always felt structurally strong, willing and able. With #2, the hip feels weak and tender but the leg is great and the muscles quite willing.
I am wondering if a lot of it relates to the surgeons choice of direction, positioning and angle of access to the joint. Also taking into consideration any existing soft tissue problems that may have developed because of pre surgery posture and activity or lack thereof. Think about how that would involve upsetting different areas of soft tissue and their interrelationships. For example #1 incision for me is much lower and shorter, #2 incision much higher, further back and longer. I'm imagining everything that is below that incision and different types of trauma. Same surgeon, same procedure on paper, same person but different hips with a varied surgical approach to the joint. Food for thought offered to maybe provide an explanation if not an answer. Are you working with a physio? All my waffle above was geared towards thinking you may benefit from a bit of a tune up and assessment of your current soft tissue health from knee to hip. A bit of help with the direction to take with your rehabilitation.