Yes, you are right, I'm not new to morphing, but I have never shared my work. This is the first forum I have ever joined as I generally despise social media, but this place is fantastic.
I'm glad you've overcome that repulsion. Visiting other places as well, I have to say this forum is one of the most optimistic, friendly and open minded communities that I know of (Just do not visit the Jordan Carver thread over at the Models/Glamour section, or you will be proven the opposite ;-) )
If you could elaborate a bit on ---"the scenario ideas are pretty nice, but since they are of such a descriptive nature, they are rather factual. Perhaps they would be even better if you can write them more as a short story or as a caption?"--- I would really appreciate that.
I'll try if I can get my opinion across: Since you did mainly elaborate the first scene, while the second is but a oneliner, let's focus on the first scenario. You describe everything from an external position, the narrator is neither the previous men magnet nor the appearing bombshell. Yet your narrator is omniscient: he knows the men magnet's thoughts and construes her facial expression. In my opinion, you need not tell the story from one figure's perspective, but it helps a lot to avoid one common pitfall: you often report instead of elaborate. One instructor once told me, we 'had to show and not tell'.
Let me give you examples from shortened passages.
You write:
*She can only stare at her rival's breasts in anger [...]*
You basically tell the reader: Okay, so now she's angry. Instead you could have elaborated a bit (let's call the men magnet 'Keira').
Hardly noticed by the raucous audience around Keira's eyes darted towards the newcomer, wandering shortly over her common face but quickly fixating on th blonde's boobs. Her mouth, which was bubbling with gossip, compliments and mocking left and right, grew into a narrow line as her bright teeth slightly bit into her lower lip. While she previously had be lasciviously reclining on the lounge benches she slouchy leaned forward, hiding her comparatively small bust even more. Averting her head with attitude, she could not stop her eyes from wandering, nervously skipping back into the corner of her eyes, darting at the intruder. Her breathing had become laboured and the vigilant bystander might have had noticed the widening of her pupils, but her defeat was obvious when her voice, several pitches too high, cracked as she said: ...
Well, that was a bit exaggerated perhaps, but it's just to get my point across. You can in most cases show the reader, what's going on, instead of telling them "Her breasts were perfect." Show them how they are round, creating the cleavage beginning at her sternum, flaring out and inward again as the curve of the breast meet again before diverging into round teardrops, while still sitting high and firm to the grip on her chest. Make the readers take in the sweet scent with his nose, while he notices all the detailed freckles on the upper half, while they can (in their mind, of course) play with the protruding and hardening nipples, which they will tickle and watch jump back into their places, or let them caress the areolae with their thumbs and make them feel the tiny bumps over the puffy area ...
Yeah, I guess you get me now. It's my opinion, and my advice. I have never before really written a story for my morphs, I'm always just glad when I finished one, and try to put it online as fast as I can. Good luck.