For architects, there is not much discipline-specific improvement in 2019. But there are some nice interface improvements to get when you upgrade from Revit 2018 to Revit 2019:

• Multi-monitor support – When working in Revit, more screen real-estate means better productivity. Less scrolling, less zooming, less trying to remember what is showing in 3D.
• Tabbed views – Clicking on a tab is a lot faster than navigating a drop-down list. This change is not perfect. When the view is a family, the tab is blank.
• Improved 3D modeling tools – Levels show in 3D, perspective views can be un-cropped and scope boxes can be assigned to 3D views.

At Yellowbryk, we focus on families, so we'll cover only family-related changes for the rest of this post.

• New BIM object libraries
  • Country-specific libraries for Germany, Austria and Switzerland
  • New and/or improved Revit families. (available in 2018.1)
    • Appliances – Oven, range, dish washer, refrigerator, clothes washer, dryer, cooktop
    • Windows – Many new shaps built with options for muntins and trim, plus bay windows, box windows and skylights.
    • Office furniture – Systems furniture, workstations, cubicles
• Remember Last Location for loading families (available in 2018.2)
  • When working on a furniture plan, loading a variety of families required navigating through the folder structure to the same place over and over again.
  • In Revit 2019, the last loaded family location is remembered. Such a small change, yet so valuable.
• Fill Pattern Dialog Improvement (available in 2018.2)
  • There are a few good tweaks implemented here:
    • The Solid Fill pattern is at the top
    • Search for patterns
    • Multi-selection of patterns
    • Resizable dialog box that remembers the new size
    • Rescale a pattern without reloading
  • I like all these changes, but my favorite is the resizable dialog box. Now I can actually read the descriptive names I've so carefully crafted for my patterns.
• Double-fill patterns – and not just for families.
• Physically-based material appearance assets
  • Designed to work with the Autodesk rendering engine.
  • Better looking renders for carpet, concrete, fabric, glass, metal, stone and wood.