If dances with good flow no longer stand out as distinctive, then do today's new dances have to feature new figures, transitions, or progressions?

I don't think so. I believe that dances without new features which exploit repetition with variation can be quite distinctive and memorable.

Sometimes, simply repeating a figure within a given context can make a dance memorable. For example, Larry Edelman's Take All the Credit and None of the Blame sets up dancers to expect a partner balance and swing, then surprises them with a balance and 1/2 hey, followed by another balance and 1/2 hey, until they finally get to swing.

More often, repeating a figure or transition in a varying way, such as swapping neighbor and partner roles, ladies and gents roles, or left and right hands, can be used to make a dance distinctive, by effectively "calling out" a figure to the dancers' attention. Here's an example:

The Windup

by Tom Lehmann

A1 (8) Neighbor do-si-do

(8) and swing

A2 (8) Long lines forward and back

(8) Circle left 3/4

B1 (8) Partner do-si-do

(8) and swing

B2 (8) Ladies chain

(8) Star left

This dance plays with the sudden release of counter-clockwise momentum, built up from common flourish of twirling counter-clockwise as one does a do-si-do (the "windup"), into the clockwise motion of a swing. (This dance works, though with less interest, if the twirling do-si-do flourish is omitted.)

This transition is repeated, first with neighbors, then with partners, while also varying how one enters these figures (from a circle with a hand tug and from two adjacent stars twirling separately).

Other dances built around partner/neighbor repetition (both using Box the Gnat) would include Sarah's Journey by Gene Hubert and Ashokan Hello by Tony Parkes.

Thus, one composition technique is to play with glossary figures with an eye towards both good flow and an interesting repetition/variation.

For example, I decided to construct a dance with contrasting 1/2 heys; the first one being the common Ladies Chain; Ladies lead right for 1/2 a Hey sequence. I wanted the other 1/2 hey to be left shoulder but, rather than simply having the gents lead it from the sides (which could lead to confusion if the dancers lost track of which hey they were doing), I decided to start it in the center.

I also took advantage of the fact that a left hey flows naturally into a right shoulder partner gypsy and swing. This gave me:

(8) Ladies chain

(8) Ladies lead right 1/2 a hey

... Neighbor swing

(8) Gents allemande left 1 1/2

(8) Pass partner right for 1/2 hey

(16) Partner gypsy and swing

... (progression)

Both the ladies and gents are now crossed over, which suggested an initial (8) Right and Left Thru. However, even with a short neighbor swing, this left no time for a progression. So, I decided to vary the heys a third way, by making the partner hey a standard "lost and found" one while the neighbor hey would be "lost and lost" to a new neighbor, becoming my progression (being in the middle of a section, this then forced the dance to become Becket).

This produced a dance with no balances or reversals of motion, so I then decided to give my dancers a bit of breather by swapping the zesty Right and Left Thru for a more leisurely Couples Promenade across the set:

Allergies

by Tom Lehmann

Becket (barely)

A1 (8) Couples promenade (across the set)

(8) Ladies chain

A2 (8) Ladies lead right 1/2 hey (to someone new)

(8) New neighbor swing

B1 (8) Gents allemande left 1 1/2

(8) Pass partner right for 1/2 hey

B2 (16) Partner gypsy and swing

Its title extends Tony Parkes' Hey Fever (which has a couples promenade, ladies chain, hey sequence) and is plural in a nod to Ken Bonner's Double Hey Fever (which features two heys). With its strong partner interaction, gypsy, and simple glossary moves, this dance can work for a final dance of an evening.

Another form of repetition and variation is the alternating dance, in which the ones and twos (or men and women) repeat each other's moves every other time through the dance. The seminal dance of this type is Alternating Corners by Jim Kitch.