What are the most important skills (both tactical and intangible) that are must-have for product marketers?

The most successful product marketers are ones who lead with empathy and take on the customer point of view.

I actually wouldn't separate out high-level GTM strategy from product/feature specific launches. The skills you've listed as high-level overall GTM (messaging, positioning, pricing, packaging, etc.) are the fundamentals to be able to launch any product or feature. Tactically all PMMs should be able to write, and present, and analyze data to make decisions that help grow revenue and support customer adoption. 

The ways in which you get it done, however, are through fostering cross-funcational relationships within your organization, understanding the goals and objectives of other teams, and working to help bridge gaps that will ultimately impact how your customers experience your products. 

Intangible: Curiosity, resilience, diplomacy, grit, and being an evangelist for your product/space. The best product marketers can flip between the forrest and the trees. They understand where their market is headed. They can speak with Executives and support reps with ease.

Tactical: Relationship building, public speaking, writing, editing, analysis/modeling, extreme attention to detail, and survey design.

I'll answer this by conveying what I look for when I hire product marketers:

1. Messaging skills - can you take complex things and make them seem simple and easily digestible
2. Writing skills - writing is an art form, and is the most important foundational skill for a PMM in my opinion
3. Storyteling - can you turn a customer use case into an interesting and memorable story
4. Influence - can you rally people around your ideas and vision
5. Collaboration skills - PMM is obviously an incredibly cross-functional discipline

Notice I didn't put in "Organizational skills" while many likely would. I think there are tools we can use to stay organized (hello ClickUp!), and I can always hire people that are super organized to project manage launches, etc. While organizational skills are clearly important, they don't make my top 5 list. 

For my #1 tip, see the answer to another question here re: what skills to develop to stand out as a PMM. tl;dr: deeply understand the marketing-SDR-sales funnel (and/or the self-serve funnel if that is important to your company) and tie your work to funnel IMPACT. The full answer unpacks this more eloquently.

Beyond that answer, there are a few other areas I’ll go into. I’ll focus mostly on intangibles…most people pick up the tactical skills through on-the-job experience.

Negotiating deliverables and deadlines. PMMs are enablers (in a good way). We enable those holding a number (Demand Gen, SDRs, Sales, etc) to hit those numbers. We have to identify and take on the most impactful work, negotiate realistic deadlines, and then HIT the deadlines so that those other functions can plan and execute. I’ve worked with PMMs over the years that were incredible experts and storytellers but often missed deadlines. They then lost credibility with cross-functional teams, and with leadership, as a result. In other cases, I’ve seen PMMs hit deadlines but they focused on things that did not have any impact (they chose pet/vanity projects, or they over-indexed on requests from PM vs GTM). The results were the same - lost credibility and tarnished internal brand. So, take the planning process very seriously, focus on impact, and honor your commitments.

Stakeholder management is also key. Shit happens, so when you do commit to deliverables, communicate early and often re: progress. Let the teams/leaders that are dependent upon your work know if there are risks to deliverables and what needs to happen to get unblocked. No one likes surprises or having to re-plan at the last minute. Make sure your stakeholders are with you along the journey.