If you don’t plan on using the internal sequencer of the a4, I don’t think it will do much for you that you can’t do elsewhere in your gear.
I feel that it comes alive when you really push and p-lock and sequence the crap out of it. The level of control and variation you can get on every parameter per step is what makes it cool. If you’re just using it as monosynths sequenced by your DT it will quickly seem redundant.
Don’t do it! 
I sold my A4mk1 a couple of years back and I now regard it as one of the most stupid things I’ve ever done!
The DT will allow you to sequence Elektron style, but as mentioned, it doesn’t give u p-lockable slides, sound locks, velocity mod etc. The A4 has this unique thing going on between the synth and sequencer that you will eventually miss.
The thing with an Analog Four is that, whether one ends up regretting selling it or not, it’s a mistake one can afford to make. I mean, looking at local second hand prices, mk1s are ~600€ and (grey) mk2s 800€ regularly. Being still in production this isn’t going to change in the foreseeable future. In other words, not a problem getting it back if one really starts missing it.
Of course it’s slightly different if you’ve bought the device new yourself and prefer to buy your gear new in general. In which case I say, whispering, with second hand prices you get more gear for the same money. 
I was stirring but you seem serious…
Facebook Aussie Wigglers is a good sell place
Faceook Aussie synth junction is another.
You can also use gumtree…
I’ve thought about trading in my Keys several times, but never give through with it. The main thing that keeps it in my setup is the CV connectivity, as I’ve been getting into modular. If you don’t modular, it might not be as useful. It’s your world, do whatever you want
I might be in the minority with this, but I really like the feel of playing the mini-keys on the A4mk2, and it sounds unlike anything else I have.
I also have a Peak and a Rev2, I think these 2 fight for similar space sonically, whereas the A4 sits in and around them.
I have a couple of particular kits now for mine, that I just adore… and they inspire new music every time I switch it on.
If it’s not for you it’s not for you… I’m not a huge fan of the Octatrack or Digitakt, I’d let both of these go before my A4 or AR (or DN)…
It does sit well in a mix, doesn’t it?
Same for me on the mk1. That little keyboard is way handier than I expected it would be.
I think an A4 is worth keeping for a lot of reasons other folks have mentioned. if you’re interested in a monosynth, why not use the A4 to do that? If you don’t like the sound or some of the workflow that might be a different story. Honestly, it sounds like you have a ton of gear so letting go of the A4 to get another synth is not really relatable to me. I’m a bit jealous of all the stuff you’ve got actually lol 
It’s been said before, but I’ve seen lots of people express interest in new gear on this forum while having lots of equipment already.
lots of people express regret of selling gear later on.
Might be worth doing some examination of what you’re hoping to achieve. maybe simplify your set up or focus solely on the A4 for a bit? I dunno. sounds like you’re interested in keeping the A4 by making this post, but who knows. I have an MK1 and I wish i had an MK2, so maybe we can trade…
I agree 100%. I find it actually very easy to create beautiful and inspiring sounds with my A4. And I also very much like the filters. Even though many forum members disagree, I find them very musical.
I don’t like keeping stuff around that I don’t use. The A4 is a pretty expensive thing to have sitting around gathering dust.
There’s nothing to be jealous of, I’m not spoiled, I worked really hard over the past decade to accumulate all my gear. I’m just trying to get rid of some gear to make room for things I’ll actually use.
The A4 just happens to overlap with other stuff in the studio. I never said it’s not cool, it’s really cool, and for the first year I had it, I loved it.
But now that I’ve figured out how to the use the DT to get Elektron sequencing on all my gear, I don’t really need the A4 sequencer, and I’m just in the studio so I don’t need the performance features.
And, the sound of it isn’t super inspiring to me. I think it sounds good, but it doesn’t do anything I can’t get out of my other synths.
That’s why I was just leaning toward something that has a completely different character than anything else I have. There’s a bunch of mono synths out there that cover different ground than what I have. And I would probably free up some cash as well.
It is mandatory for any immigrants coming to Australia to retain their A4 for the life of their visit, so you must keep it, no option 
i hope i didn’t come across as insulting or demeaning. I was just joking around about being jealous or whatever. It sounds like you’re leaning towards selling and that might be a smart move. 
Haha
Fair enough
Haha
No not at all, I just try not to compare myself or what I have to other folks.
Everyone’s situation is different. I’ve been fortunate enough to make money making music, so I write off a fair bit of equipment every year as business expense.
I wasn’t offended or anything, it’s all good bro.
if you’re making money with music, sell it all and work only in a DAW like everyone else 
but don’t sell the A4.
I have a DN and an A4mk2. I LOVE the DN and I like the A4 a lot, but something about the A4 doesn’t quite gel as much. Lately the deluge has been taunting me from the internet…
True, that’s GAS, but also I tend to have a very analytical take on gear, offloading stuff that doesn’t address a certain thing. I think that’s why the deli is interesting, it kinda does the elektron thing, but takes is so much further. Zooming in to do ratchet type stuff… oh my days.
I always start by asking myself (once GAS made me get something) - why? What does it add? What doesn’t it add?
The only emotional instrument connections i have are with my folk ones (mandolins, tenor guitars) so with electronic gear I am glad I don’t fall in love too hard.
I also have a summit, and I wish I’d hung on for the re-stock of Peak…
But I think the difference now to when i was young is that i don’t over obsess about the ‘right’ decision.
I think about what i really want, once my instrument honeymoon period is done. Also I buy second hand where poss, so as not to lose too much - my A4 was 2nd hand.
I’m not only music for money. I also make music for fun still 
Honestly, a lot of it is done in the DAW.
But I don’t find scrolling plug-in presets as inspiring as turning knobs, so I start on hardware whenever I can.
This is kind of how I think about gear as well
Nothing is that precious, they’re just tools
Except my J-45 