I agree with the previous comments. Your tracks are fun and happy, but I'm not feeling that Studio 54 vibe. I think they are a better fit for a funk/soul pitch. I got similar feedback as you on the style of some of my submissions. I tried to channel different artists when creating them, and the ones that were returned were more late '70s disco, and the screener felt they were better for funk/soul/electro pop pitches. So, when they say 70's disco, maybe the takeaway is that they mean early '70s. I was thinking Blondie and ABBA for two of my pitches which would be at the tail end of the 70's and into the early 80s, and those were returned.
I think you should be fine with pitching these going forward for funk/soul pitches, but I'd still address the comments about the production. Disco was my life in the 70's, so I thought I'd share more detailed feedback.
Here are some things you could consider IMHO tl;dr:
Frantic/Virtual: I don't think your tracks are frantic. In disco, though, there is always a very solid signature that can be either a riff or melodic thing (strings in the intro of Car Wash, or Heaven Must Be Missing an Angel for example). That gets repeated through out in the turnarounds, etc. I don't feel a definitive signature in the tracks.
Reverb: your tracks were pretty wet, which is going to muddy up the horn stabs/etc. I usually use something drier, like a scoring stage reverb as opposed to a hall reverb. Editors can add their own reverb if they decide it's needed.
Drums: Disco drums are tight and dry, and the basic groove is pretty specific - 4 on the floor, open high hat on the upbeats of 2 and 4, and closed on 2 and 4 with the snare. I used Toontrack Superior Drummer 3 for my sound and grooves, and use a dry kit, plus tweak the envelopes on the kick and toms so that they don't ring out much. Finally, I double the kick with a subkick sound so I can pump the bottom end up to get that disco "thump".
Horns: Your horn lines have more sustained notes in them, and your stabs ring out a lot. You could shorten the stabs up quite a bit. For sounds, I use either Kontakt Session Horns, or for more intricate programming I use Mojo2 Horns. Mojo2 has stab articulations which work great. That's a plugin that has more of a learning curve but they sound great.
Guitar: You have a lot of guitar, which is usually used more for the comping (a la Nile Rodgers) as opposed to being in the forefront. You are using them more in a funk context which is also why the screener might have felt they were more funk than disco.
Bass: The bass groove usually has that walking 8ths octave vibe, and the high note of the octaves are usually popped. I use either the funk bass from the Kontakt Factory Library or a funk bass from EastWest and then compress/eq it to keep it tight.
Strings: I didn't hear any strings. They are used heavily in early disco, and can carry a lot of the melody weight. Doubling with glockenspiel and/or flute is used a ton. Tavares is one of my go-to examples for early disco that uses these techniques. For strings, I use Disco Strings for Kontakt by Keyboard Waves (
Disco Strings for Kontakt). I also use Kontakt Session Strings, but I like the disco strings better for these kinds of projects, they are very playable and responsive.
Percussion: Hand claps on 2 and 4, cowbell on the beat at least in the chorus (not always, but KC used it all the time). Latin percussion is always good to add, especially in a break. I use Toontracks Latin Percussion EZX for all of that.
This is a lot, but you complimented my tracks and just wanted to share my approach, I hope there are things you find helpful. Meanwhile, pitch those tracks for funk/soul!