[Kungsgeten]

When I've tinkered with system recently I have thought about removing weak 5332 hands from the 1M openings, making them unbalanced. There are several ways to do this, and the most common is probably to put them together with the other balanced hands in a nebulous 1m opening (this is in a strong NT context). Another solution I've seen (Larrry Lowell played this) is to open 2M with 5332 and weak NT range. What I haven't seen though, is to use 2D as a "multi" with these hands. Example:

1C = Clubs or 12-14 NT or 18-19 NT (may have 5M if 18-19).
1D = Unbal NAT.
1M = Unbal NAT.
1NT = 15-17.
2C = Strong.
2D = 11-14 with 5M332.
2M = Weak.

Perhaps the downsides when they interfere are to big (compared to playing 2M as the balanced variant). But it would seem like there's more wiggle-room for part-scores:

2D--
Pass = (4)5+D. The balanced multi could be frequently passed, which makes it dangerous for the opponents to pass with values.
2M = Pass/correct, 2+ suit.
..2S = Spades. 2NT and 3S INV. 3X to play.
..2NT = Min hearts (over 2S). 3X to play.
..3C = Max hearts (over 2S). 3X to play.
2NT = Puppet to 3C. To play 3C or GF with own suit.
3C = INV+ asking bid. 3D min hearts, 3H min spades, 3S max hearts, 3NT max spades.
3D = Bid the major you don't have.
3H = Pass/correct.
3S = Puppet to 3NT.
3NT = To play.
4C = Transfer to your suit.
4D = Bid your suit.
Game = To play.

A downside is that you can't stop in 2S when responder has spades (compared to playing 2H as 5332, and the 2S response as NF).

[HardVector]

If you want a way to deal with 5332 hands with 5 card majors, you might want to look at GUS. They put those into the 1n bid, making 1n 12-16. If you have 12-14, you have a 5 card major, otherwise, you have 15-16 (or a very good 14). We have found it's VERY beneficial when partner opens 1M we know that it's truly unbalanced. They have 2 ways of doing it, their relay structure and a "simple" structure. Below is the simple one: responder's bids in {paren}

1n (12-16 balanced)

{2c} - Asking, inv+

2d - minimal (14-15), no 5 card major
{2h/2s} - weak, scramble
{2n} - inv
{3c} - Stayman
{3d/3h} - transfers

2h/2s - 12-14, 5332 major suit
- further bids natural, NF

2n - max GF (15-16), no 5 card major
{3c} - Stayman
{3d/3h} - transfers

3h/3s - max GF, 5332 majors

This version has a flaw in that if partner responds 3s you don't have a way to figure out if partner has 3 hearts for a 5/3 heart fit. The more complicated version solves this. BTW, you are going to want to run through the asking bid with any inv+ hand with 5 card majors to clarify partner's hand. Inv+ is assuming partner has a 15-16 pt hand, if it turns out that partner is 12-14, you may not have enough to bid again.

Anyway, that's another way to skin the cat if it interests you.

[nullve]

 Kungsgeten, on 2019-September-01, 05:05, said:

A downside is that you can't stop in 2S when responder has spades (compared to playing 2H as 5332, and the 2S response as NF).

Then how about something based on

1♣ = NAT or 11-13/17-19 BAL
1♦ = NAT unBAL
1M = 5+ M
1N = 14-16 BAL
2♣ = 11-13, 5S(332), 20-21 BAL or any GF
2♦ = Weak Multi
2♥ = 11-13, 5H(332)
2♠ = ?
2N = 22-24 BAL

2♣-?:

2♦ = a) wants to play 2♥ opposite 20-21 BAL b) GF opposite 20-21 BAL, does not want to play 2♥ opposite 11-13
...2♥ = 11-13, 5S(332) OR 20-21 BAL OR GF, 5+ H, unBAL
......P = a)
......2♠ = d), P/C
.........P = 11-13
.........2N = 20-21 BAL
.........3♣+ = GF, 5+ H, NAT
......2N+ = d), does not want to play 2♠ opposite 11-13
2♥ = c) wants to play 2♠ opposite 11-13 d) to play opposite 11-13 BAL, else FG
...P = 11-13
...2♠ = 20-21 BAL
......P = c)
......other = d)
...2N+ = GF
(...)

?

(The 2♣-2♦; 2♥ "Kokish or weak option with spades" idea is stolen from Glen Ashton's (glen's) Wicked Weak/Strong 2♣ opening.)

[Kungsgeten]

 nullve, on 2019-September-28, 04:24, said:

Then how about something based on

1♣ = NAT or 11-13/17-19 BAL
1♦ = NAT unBAL
1M = 5+ M
1N = 14-16 BAL
2♣ = 11-13, 5S(332), 20-21 BAL or any GF
2♦ = Weak Multi
2♥ = 11-13, 5H(332)
2♠ = ?
2N = 22-24 BAL

That could work for sure, though it wouldn't work in a system where 2♣ is needed as something else. One "upside" in the balanced multi had to do with the Swedish system regulations, where a bid that is always balanced gets 2 "artificiality dots" while a normal multi gets 3. Another option could be:

2♦ = Weak hearts or 11-13 5S(332)
2♥ = 11-13 5H(332)
2♠ = Weak.