2 instruments or upgrade to Standard?

I bought the upgrade when it was on sale.

I love to fiddle with the microphones like a real sound engineer. I learned a lot about the different characteristics of microphones.
I watch tutorials about how real pianos are mirophoned and giggle like a child when i manage to get similar results. Great fun.

I also like the ability to load impulse responses. There are gazillions of free reverb files out there.
Ever wanted to play in the milano scala or the sidney opera? No problem with the IR-files. Feel like Evgeny Kissin himself.

Ever wanted to try some weird esotheric tuning to check if your happy-molecules vibrate (like Adam Neely did)
or make history by inventing your very own Romariozen tuning? Go for it!

In my opinion the upgrade to Standard really unleashes the power of Pianoteq.

Pianoteq Standard is my little laboratory kit, i love it so much.

Isn't there a free piano in the upgrade included now anyways? The upgrade (during sale) was a no brainer for me.

i started out with standard so don't have any experience with stage.  i'm not an audio pro, but i can unequivocally say it's fun to have all the parameters of standard available to play around with.  it really opens new doors.

I think you should at least consider it. I bought standard and the option to change the microphones makes a huge difference to me. I didn't care much for the microphone settings at first, but then I found out that small changes to the setup can make quite the difference on my piano. So I made setups that sound "optimal" to my ears for playing with and without headphones. Also I generally love a little bit of tinkering with the presets .

In Standard you can also load any Pro FXPs (you just can't edit them the way you can in Pro), which allows you access to anything the community creates based on the Instrument Packs you already have and that's as much or more flexibility as a new instrument packs (which you can always save up for one every few months after making the upgrade).  Since there's a new version out, I'd recommend upgrading to Standard for the extra value of not needing to upgrade your Stage license for extra (if you haven't bought a new version in the last year).

I'm curious about the Steinways with respect to a Player > Standard upgrade. I understand this upgrade would include one additional instrument pack, but unclear if the "Steinway D" showing amongst the currently licensed packs under Player 6 will translate to this new Steinway pack, part of it (i.e. not the NY one), or if a legacy "D" will be included and the new Steinways must be additionally purchased or selected.

Well, as soon as I had seen the PTQ 7 release I initially purchased it

If I get the OP correctly, I've had the same question. I was hoping that an upgrade to Standard would allow new instrument pack choices but it does not. While I like both the Steinway D and K2, being able to add the Steingrabber and the Rhodes would have closed the deal.
Also while I may be wrong, upgrading from Stage 6 to Stsndard 7 looks like it involves 2 upgrade purchases.
So for moi, I'll stick with Stage, get 7 with the added NY D and put the rest toward the SWAM Strings. I'm hoping I can get all 5 to play simultaneously on a couple of MacBook i5s if I Ethernet them together.
Regards from Sunny Florida.

RS
MidiOpera.com

Edit: rereading Nic Fogwall's response looks like upgrading from Stage 6 to Standard results in a Standard 7 license. I will update when I hear back from him.

I have the same question regarding instrument packs.

I upgraded my standard from 6 to 7. I have had 2 packs in the initial version (stage 5), upgraded very soon to standard, there was no choice to select a third one, upgraded to V6, bought a 3rd pack at full price, upgraded now to V7 and do NOT have had the oportunity to select a third package included to select.

Is this some error/bug?

No, since you upgraded your Pianoteq (Standard) from version 6 to version 7. You did not upgrade your Pianoteq tier, if I understood you correctly. You were at Standard and you’re still at Standard.
Since 2019, you get an extra pack if you upgrade your Pianoteq tier from Stage to Standard or from Standard to Pro. One may even get two extra packs if one decides to upgrade from Stage to Pro.