The problem with Talonflame is /not/ that it's just a simple portmanteau of two aspects of the creature's design (as this naming practice is fairly par for the course), but it's that the two words being used do not create a single word when combined. There's no "flow".
Take Beedrill: It's just "Bee" and "Drill", but bee flows naturally into drill, from vowel to consonant. Take Charmander: It's just "Char" (as in char-grilled) and the ending of "Salamander", but combined it again fits together like a whole new word. Take Voltorb: It's just "Volt" and "Orb", but the consonant "t" flows into the vowel "o" like a glove.
Then take Talonflame: The "n" and "f" do not create a continuous sound together, creating a separation in the word that makes it sound like two when it's supposed to be one. And being that the separation occurs exactly where each descriptive word starts and stops, it makes "Talonflame" sound like a Deviantart-tier OC name.
Examples of "Talonflame"-ified names - with unwieldy portmanteaus - would be Waspdrill, Tortcannon, Elecball and Chargecko.
So the problem, really, is that it's a /bad/ portmanteau.
